Big Ecosystem Shifts from Climate Change

Big Ecosystem Shifts from Climate Change

  12:47:00 AM    Science Lover

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By 2100, global climate change will modify plant communities covering almost half of Earth's land surface and will drive the conversion of nearly 40 percent of land-based ecosystems from one major ecological community type -- such as forest, grassland or tundra -- toward another, according to a new NASA and university computer modeling study.

Predicted percentage of ecological landscape
being driven toward changes in plant species
as a result of projected human-induced climate
change by 2100. (Credit: NASA/JPL-Caltech)

Researchers from NASA's Jet Propulsion Laboratory and the California Institute of Technology in Pasadena, Calif., investigated how Earth's plant life is likely to react over the next three centuries as Earth's climate changes in response to rising levels of human-produced greenhouse gases. Study results are published in the journal Climatic Change.

The model projections paint a portrait of increasing ecological change and stress in Earth's biosphere, with many plant and animal species facing increasing competition for survival, as well as significant species turnover, as some species invade areas occupied by other species. Most of Earth's land that is not covered by ice or desert is projected to undergo at least a 30 percent change in plant cover -- changes that will require humans and animals to adapt and often relocate.

In addition to altering plant communities, the study predicts climate change will disrupt the ecological balance between interdependent and often endangered plant and animal species, reduce biodiversity and adversely affect Earth's water, energy, carbon and other element cycles.

"For more than 25 years, scientists have warned of the dangers of human-induced climate change," said Jon Bergengren, a scientist who led the study while a postdoctoral scholar at Caltech. "Our study introduces a new view of climate change, exploring the ecological implications of a few degrees of global warming. While warnings of melting glaciers, rising sea levels and other environmental changes are illustrative and important, ultimately, it's the ecological consequences that matter most."

When faced with climate change, plant species often must "migrate" over multiple generations, as they can only survive, compete and reproduce within the range of climates to which they are evolutionarily and physiologically adapted. While Earth's plants and animals have evolved to migrate in response to seasonal environmental changes and to even larger transitions, such as the end of the last ice age, they often are not equipped to keep up with the rapidity of modern climate changes that are currently taking place. Human activities, such as agriculture and urbanization, are increasingly destroying Earth's natural habitats, and frequently block plants and animals from successfully migrating.

To study the sensitivity of Earth's ecological systems to climate change, the scientists used a computer model that predicts the type of plant community that is uniquely adapted to any climate on Earth. This model was used to simulate the future state of Earth's natural vegetation in harmony with climate projections from 10 different global climate simulations. These simulations are based on the intermediate greenhouse gas scenario in the United Nations' Intergovernmental Panel on Climate Change Fourth Assessment Report. That scenario assumes greenhouse gas levels will double by 2100 and then level off. The U.N. report's climate simulations predict a warmer and wetter Earth, with global temperature increases of 3.6 to 7.2 degrees Fahrenheit (2 to 4 degrees Celsius) by 2100, about the same warming that occurred following the Last Glacial Maximum almost 20,000 years ago, except about 100 times faster. Under the scenario, some regions become wetter because of enhanced evaporation, while others become drier due to changes in atmospheric circulation.

The researchers found a shift of biomes, or major ecological community types, toward Earth's poles -- most dramatically in temperate grasslands and boreal forests -- and toward higher elevations. Ecologically sensitive "hotspots" -- areas projected to undergo the greatest degree of species turnover -- that were identified by the study include regions in the Himalayas and the Tibetan Plateau, eastern equatorial Africa, Madagascar, the Mediterranean region, southern South America, and North America's Great Lakes and Great Plains areas. The largest areas of ecological sensitivity and biome changes predicted for this century are, not surprisingly, found in areas with the most dramatic climate change: in the Northern Hemisphere high latitudes, particularly along the northern and southern boundaries of boreal forests.

"Our study developed a simple, consistent and quantitative way to characterize the impacts of climate change on ecosystems, while assessing and comparing the implications of climate model projections," said JPL co-author Duane Waliser. "This new tool enables scientists to explore and understand interrelationships between Earth's ecosystems and climate and to identify regions projected to have the greatest degree of ecological sensitivity."

"In this study, we have developed and applied two new ecological sensitivity metrics -- analogs of climate sensitivity -- to investigate the potential degree of plant community changes over the next three centuries," said Bergengren. "The surprising degree of ecological sensitivity of Earth's ecosystems predicted by our research highlights the global imperative to accelerate progress toward preserving biodiversity by stabilizing Earth's climate."

JPL is managed for NASA by the California Institute of Technology in Pasadena.

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Global Warming Is Real, New Analysis Confirms

Global Warming Is Real, New Analysis Confirms

  9:38:00 PM    Science Lover

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Global warming is real, according to a major study released Oct. 20. Despite issues raised by climate change skeptics, the Berkeley Earth Surface Temperature study finds reliable evidence of a rise in the average world land temperature of approximately 1°C since the mid-1950s.

Comparison of data showing decadal land-surface average world temperature changes from 15 different sources, some going back as far as 1800. (Credit: Image courtesy of Berkeley Earth Surface Temperature)

Analyzing temperature data from 15 sources, in some cases going as far back as 1800, the Berkeley Earth study directly addressed scientific concerns raised by skeptics, including the urban heat island effect, poor station quality, and the risk of data selection bias.

On the basis of its analysis, according to Berkeley Earth's founder and scientific director, Professor Richard A. Muller, the group concluded that earlier studies based on more limited data by teams in the United States and Britain had accurately estimated the extent of land surface warming.

"Our biggest surprise was that the new results agreed so closely with the warming values published previously by other teams in the U.S. and the U.K.," Muller said. "This confirms that these studies were done carefully and that potential biases identified by climate change skeptics did not seriously affect their conclusions."

Previous studies, carried out by NOAA, NASA, and the Hadley Center, also found that land warming was approximately 1°C since the mid-1950s, and that the urban heat island effect and poor station quality did not bias the results. But their findings were criticized by skeptics who worried that they relied on ad-hoc techniques that meant that the findings could not be duplicated. Robert Rohde, lead scientist for Berkeley Earth, noted that "the Berkeley Earth analysis is the first study to address the issue of data selection bias, by using nearly all of the available data, which includes about 5 times as many station locations as were reviewed by prior groups."

Elizabeth Muller, co-founder and Executive Director of Berkeley Earth, said she hopes the Berkeley Earth findings will help "cool the debate over global warming by addressing many of the valid concerns of the skeptics in a clear and rigorous way." This will be especially important in the run-up to the COP 17 meeting in Durban, South Africa, later this year, where participants will discuss targets for reducing Greenhouse Gas (GHG) emissions for the next commitment period as well as issues such as financing, technology transfer and cooperative action.

The Berkeley Earth team includes physicists, climatologists, and statisticians from California, Oregon, and Georgia. Rohde led the development of a new statistical approach and what Richard Muller called "the Herculean labor" of merging the data sets. One member of the group, Saul Perlmutter, was recently announced as a winner of the 2011 Nobel Prize in Physics (for his work in cosmology).



The Berkeley Earth study did not assess temperature changes in the oceans, which according to the Intergovernmental Panel on Climate Change (IPCC) have not warmed as much as land. When averaged in, they reduce the global surface temperature rise over the past 50 years -- the period during which the human effect on temperatures is discernable -- to about two thirds of one degree Centigrade.

Specifically, the Berkeley Earth study concludes that:

• The urban heat island effect is locally large and real, but does not contribute significantly to the average land temperature rise. That's because the urban regions of Earth amount to less than 1% of the land area.
• About 1/3 of temperature sites around the world reported global cooling over the past 70 years (including much of the United States and northern Europe). But 2/3 of the sites show warming. Individual temperature histories reported from a single location are frequently noisy and/or unreliable, and it is always necessary to compare and combine many records to understand the true pattern of global warming.
• The large number of sites reporting cooling might help explain some of the skepticism of global warming," Rohde commented. "Global warming is too slow for humans to feel directly, and if your local weather man tells you that temperatures are the same or cooler than they were a hundred years ago it is easy to believe him." In fact, it is very hard to measure weather consistently over decades and centuries, and the presence of sites reporting cooling is a symptom of the noise and local variations that can creep in. A good determination of the rise in global land temperatures can't be done with just a few stations: it takes hundreds -- or better, thousands -- of stations to detect and measure the average warming. Only when many nearby thermometers reproduce the same patterns can we know that the measurements were reliably made.
• Stations ranked as "poor" in a survey by Anthony Watts and his team of the most important temperature recording stations in the U.S., (known as the USHCN -- the US Historical Climatology Network), showed the same pattern of global warming as stations ranked "OK." Absolute temperatures of poor stations may be higher and less accurate, but the overall global warming trend is the same, and the Berkeley Earth analysis concludes that there is not any undue bias from including poor stations in the survey.

Four scientific papers setting out these conclusions have been submitted for peer review and will form part of the literature for the next IPCC report on Climate Change. They can be accessed on: www.BerkeleyEarth.org. A video animation graphically shows global warming around the world since 1800.

Berkeley Earth is making its preliminary results public, together with its programs and dataset, in order to invite additional scrutiny. Elizabeth Muller said that "one of our goals is to make the science behind global warming readily accessible to the public." Most of the data were previously available on public websites, but in so many different locations and different formats that most people could access only a small subset of the data. The merged database, which combines 1.6 billion records, is now accessible from the Berkeley Earth website: www.BerkeleyEarth.org .

What Berkeley Earth has not done is make an independent assessment of how much of the observed warming is due to human actions, Richard Muller acknowledged. As a next step, Berkeley Earth plans to address the total warming of the oceans, with a view to obtaining a more accurate figure for the total amount of global warming observable.

More information about Berkeley Earth is available at www.BerkeleyEarth.org.

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Report Faults BBC Science Coverage

Report Faults BBC Science Coverage

  12:33:00 AM    Science Lover

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Journalists should focus more on accurately representing the science of climate change and vaccinations and less on impartiality, a new review finds.

Meltic Arctic sea ice
NASA Godard Space Flight Center

There may be two sides to every story, but sometimes only one is right. That’s the gist of a new review of BBC’s science coverage, which suggests journalists should focus more on accurately presenting the scientific consensus and less on presenting both sides on controversial issues such as climate change, genetically engineered foods, or the discredited link between vaccines and autism.

Overall, however, the review, which was commissioned by the BBC Trust, praised BBC’s science coverage. But the analysis of 8 weeks of media content conducted by Imperial College London geneticist Steve Jones did highlight several areas for improvement. In addition to giving too much space to fringe views such as climate change skepticism, the report also faulted the media outlet for lacking strong science contacts and for depending too heavily on press releases. The BBC has reviewed the findings and is already on board with one of its recommendations: hiring a science news editor, ScienceInsider reports.

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Climate will damage reefs at 'different rates'

Climate will damage reefs at 'different rates'

  7:15:00 PM    Science Lover

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Climate change and acidifying ocean water are likely to have a highly variable impact on the world's coral reefs in space, time and diversity, according to an international team of coral scientists, including UQ researchers.

Reefs are naturally highly diverse and resilient

The picture that is emerging from studies of past coral extinctions and present impacts on today's reef systems is complex and subtle.

It will demand much more sophisticated management to preserve reefs intact, the team of scientists said in a paper in the international journal Science.

“New research confirms that coral reefs…. are indeed threatened by climate change, but that some current projections of global-scale collapse of reefs within the next few decades probably overestimate the rapidity and uniformity of the decline,” the researchers said.

“A considered view of all the most recent evidence suggests that some coral reef systems will decline more rapidly – especially those subject to other human pressures such as overfishing," said lead author Professor John Pandolfi of the ARC Centre of Excellence for Coral Reef Studies and The University of Queensland..

"However, others may change in composition, but manage to persist for longer.”

The paper, “Projecting coral reef futures under global warming and ocean acidification” by John M. Pandolfi, Sean R. Connolly, Dustin J. Marshall and Anne L. Cohen appears in the latest issue of the journal Science.

“Coral reefs occupy a small part of the world's oceans, yet harbor a hugely disproportionate amount of its biodiversity,” the researchers said.

“More than 450 million people from 109 countries live close to coral reefs, which provide important sources of ecosystem goods and services for these communities.

“But reefs have suffered degradation from human over-exploitation and pollution over centuries to millennia, degradation that has accelerated in the last 50 years.

"Global warming and ocean acidification are now compounding these threats.”

However reefs are naturally highly diverse and resilient, and are likely to respond to the changed conditions in different ways and at varying rates.

The research paper says that past extinction crises in coral reef ecosystems appeared to coincide with episodes of rapid global warming and ocean acidification.

"This has led some to predict rapid, dramatic, global-scale losses of coral reefs.

“Widespread degradation of reefs is already underway," said another of the study authors, Professor Sean Connolly of the ARC Center of Excellence for Coral Reef Studies and James Cook University.

"However, rates of future decline will be highly variable, because coral reefs are naturally highly diverse with some species able to cope with change more than others.

Moreover, changes in ocean and climate conditions will be different in different regions, and the partnership between corals and their symbiotic algae has variable capacity to adapt to changing conditions.”

The researchers said that evolution and genetic change in both creatures could make them more tolerant of major changes in ocean temperature and chemistry – but, paradoxically, it could also accelerate the decline of reef species.

However, human management was necessary to improve the corals' chances.

Actions that improved coral diversity would tend to make reefs more resilient.

The researchers also noted that large populations of reef species, not already stressed by overfishing or coastal runoff, were likely to be better able to adapt to the challenges of climate change.



“This makes the overall picture extraordinarily complex," Professor Pandolfi said.

"We do not yet have a model that explains the full spectrum of reef responses everywhere."

The researchers highlighted some critical knowledge gaps, including the effects of climate change on interactions between species, and the potential rates of adaptation of reef species to warmer and more acidic conditions.

“Our ability to continue to improve our projections of climate change effects on coral reefs depends especially on advances in our understanding of these areas,” Professor Connolly said.

“We think it would be best if the world prepares itself for a range of possible impacts and responses on reefs, and manages them accordingly, if we are to give our corals their best possible chance of survival through what we know from geological history is bound to be a very stressful era of environmental change.”

The researchers said that the best and most achievable thing people could do for coral reefs to deal with climate change was to seek to manage them well.

“However, slowing rates of climate change, and reducing the strong selection imposed by human impacts such as fishing and coastal development will remain critical to the long-term persistence of coral reef ecosystems,” they said.

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Striking Ecological Impact on Canada's Arctic Coastline Linked to Global Climate Change

Striking Ecological Impact on Canada's Arctic Coastline Linked to Global Climate Change

  1:16:00 PM    Science Lover

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Scientists from Queen's and Carleton universities head a national multidisciplinary research team that has uncovered startling new evidence of the destructive impact of global climate change on North America's largest Arctic delta.

Dead vegetation killed by the 1999 storm surge is in stark
contrast to the vegetation along the edges of waterways
that receive regular freshwater (and thus survived the
damage). (Credit: Trevor Lantz, University of Victoria)

"One of the most ominous threats of global warming today is from rising sea levels, which can cause marine waters to inundate the land," says the team's co-leader, Queen's graduate student Joshua Thienpont. "The threat is especially acute in polar regions, where shrinking sea ice increases the risk of storm surges."

By studying growth rings from coastal shrubs and lake sediments in the Mackenzie Delta region of the Northwest Territories -- the scene of a widespread and ecologically destructive storm surge in 1999 -- the researchers have discovered that the impact of these salt-water surges is unprecedented in the 1,000-year history of the lake.

"This had been predicted by all the models and now we have empirical evidence," says team co-leader Michael Pisaric, a geography professor at Carleton. The Inuvialuit, who live in the northwest Arctic, identified that a major surge had occurred in 1999, and assisted with field work.

The researchers studied the impact of salt water flooding on alder bushes along the coastline. More than half of the shrubs sampled were dead within a year of the 1999 surge, while an additional 37 per cent died within five years. A decade after the flood, the soils still contained high concentrations of salt. In addition, sediment core profiles from inland lakes revealed dramatic changes in the aquatic life -- with a striking shift from fresh to salt-water species following the storm surge.

"Our findings show this is ecologically unprecedented over the last millennium," says Queen's biology professor and team member John Smol, Canada Research Chair in Environmental Change and winner of the 2004 NSERC Herzberg Gold Medal as Canada's top scientist. "The Arctic is on the front line of climate change. It's a bellwether of things to come: what affects the Arctic eventually will affect us all."

Since nearly all Arctic indigenous communities are coastal, the damage from future surges could also have significant social impacts. The team predicts that sea ice cover, sea levels and the frequency and intensity of storms and marine storm surges will become more variable in the 21st century.

Other members of the team include Trevor Lantz from the University of Victoria, Steven Kokelj from Indian and Northern Affairs Canada, Steven Solomon from the Geological Survey of Canada and Queen's undergraduate student Holly Nesbitt. Their findings are published in the Proceedings of the National Academy of Sciences.

Research funding comes from the Natural Sciences and Engineering Research Council of Canada (NSERC), the Polar Continental Shelf Program, the Cumulative Impact Monitoring Program, and Indian and Northern Affairs Canada.

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Climate Change Implicated in Decline of Horseshoe Crabs

Climate Change Implicated in Decline of Horseshoe Crabs

  8:32:00 PM    Science Lover

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A distinct decline in horseshoe crab numbers has occurred that parallels climate change associated with the end of the last Ice Age, according to a study that used genomics to assess historical trends in population sizes.

Horseshoe crabs congregate annually at Delaware Bay. (Credit: Greg Breese, U.S. Fish and Wildlife Service)

The new research also indicates that horseshoe crabs numbers may continue to decline in the future because of predicted climate change, said Tim King, a scientist with the U.S. Geological Survey and a lead author on the new study published in Molecular Ecology.

While the current decline in horseshoe crabs is attributed in great part to overharvest for fishing bait and for the pharmaceutical industry, the new research indicates that climate change also appears to have historically played a role in altering the numbers of successfully reproducing horseshoe crabs. More importantly, said King, predicted future climate change, with its accompanying sea-level rise and water temperature fluctuations, may well limit horseshoe crab distribution and interbreeding, resulting in distributional changes and localized and regional population declines, such as happened after the last Ice Age.

"Using genetic variation, we determined the trends between past and present population sizes of horseshoe crabs and found that a clear decline in the number of horseshoe crabs has occurred that parallels climate change associated with the end of the last Ice Age," said King.

The research substantiated recent significant declines in all areas where horseshoe crabs occur along the West Atlantic Coast from Maine to Florida and the eastern Gulf of Mexico, with the possible exception of a distinct population along the Yucatan Peninsula of Mexico.

These findings, combined with the results of a 2005 study by King and colleagues, have important implications for the welfare of wildlife that rely on nutrient-rich horseshoe crab eggs for food each spring.

For example, Atlantic loggerhead sea turtles, which used to feed mainly on adult horseshoe crabs and blue crabs in Chesapeake Bay, already have been forced to find other less suitable sources of food, perhaps contributing to declines in Virginia's sea turtle abundance. Additionally, horseshoe crab eggs are an important source of food for millions of migrating shorebirds. This is particularly true for the red knot, an at-risk shorebird that uses horseshoe crab eggs at Delaware Bay to refuel during its marathon migration of some 10,000 miles. Since the late 1990s, both horseshoe crabs and red knot populations in the Delaware Bay area have declined, although census numbers for horseshoe crabs have increased incrementally recently.

"Population size decreases of these ancient mariners have implications beyond the obvious," King said. "Genetic diversity is the most fundamental level of biodiversity, providing the raw material for evolutionary processes to act upon and affording populations the opportunity to adapt to their surroundings. For this reason, the low effective population sizes indicated in the new study give one pause."

These studies should help conservation managers make better-informed decisions about protecting horseshoe crabs and other species with a similar evolutionary history. For example, the 2005 study indicated males moved between bays but females did not, suggesting management efforts may best be targeted at local populations instead of regional ones since an absence of enough females may result in local extinctions.

"Consequently, harvest limitations on females in populations with low numbers may be a useful management strategy, as well as relocating females from adjacent bays to help restore certain populations," King said. "Both studies highlight the importance of considering both climatic change and other human-caused factors such as overharvest in understanding the population dynamics of this and other species."

Background on Horseshoe Crabs

Horseshoe crabs are not crabs at all -- in fact, they are more closely related to spiders, ticks and scorpions. While historically horseshoe crabs have been used in fertilizer, most horseshoe crab harvest today comes from the fishing industry, which uses the crab as bait, and the pharmaceutical industry, which collects their blood for its clotting properties. While the crabs are returned after their blood is taken, the estimated mortality rate for bled horseshoe crabs can be as high as 30 percent.

The research was published in the June issue of Molecular Ecology and was authored by Søren Faurby (Aarhus University, Denmark), Tim King, Matthias Obst (University of Gothenburg, Sweden) and others.

The 2005 study was published in the Transactions of the American Fisheries Society and authored by Tim King, Mike Eackles Adrian Spidle (USGS) and Jane Brockman (University of Florida).

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El Niños Are Growing Stronger, NASA/NOAA Study Finds

El Niños Are Growing Stronger, NASA/NOAA Study Finds

  10:17:00 AM    Science Lover

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A relatively new type of El Niño, which has its warmest waters in the central-equatorial Pacific Ocean, rather than in the eastern-equatorial Pacific, is becoming more common and progressively stronger, according to a new study by NASA and NOAA. The research may improve our understanding of the relationship between El Niños and climate change, and has potentially significant implications for long-term weather forecasting.

Deviations from normal sea surface temperatures (left) 
and sea surface heights (right) at the peak of the 2009-2010 
central Pacific El Niño, as measured by NOAA polar orbiting 
satellites and NASA's Jason-1 spacecraft, respectively. The 
warmest temperatures and highest sea levels were located in 
the central equatorial Pacific. Image credit: 
(Credit: NASA/JPL-NOAA)

Lead author Tong Lee of NASA's Jet Propulsion Laboratory, Pasadena, Calif., and Michael McPhaden of NOAA's Pacific Marine Environmental Laboratory, Seattle, measured changes in El Niño intensity since 1982. They analyzed NOAA satellite observations of sea surface temperature, checked against and blended with directly-measured ocean temperature data. The strength of each El Niño was gauged by how much its sea surface temperatures deviated from the average. They found the intensity of El Niños in the central Pacific has nearly doubled, with the most intense event occurring in 2009-10.

The scientists say the stronger El Niños help explain a steady rise in central Pacific sea surface temperatures observed over the past few decades in previous studies-a trend attributed by some to the effects of global warming. While Lee and McPhaden observed a rise in sea surface temperatures during El Niño years, no significant temperature increases were seen in years when ocean conditions were neutral, or when El Niño's cool water counterpart, La Niña, was present.

"Our study concludes the long-term warming trend seen in the central Pacific is primarily due to more intense El Niños, rather than a general rise of background temperatures," said Lee.

"These results suggest climate change may already be affecting El Niño by shifting the center of action from the eastern to the central Pacific," said McPhaden. "El Niño's impact on global weather patterns is different if ocean warming occurs primarily in the central Pacific, instead of the eastern Pacific.

"If the trend we observe continues," McPhaden added, "it could throw a monkey wrench into long-range weather forecasting, which is largely based on our understanding of El Niños from the latter half of the 20th century."

El Niño, Spanish for "the little boy," is the oceanic component of a climate pattern called the El Niño-Southern Oscillation, which appears in the tropical Pacific Ocean on average every three to five years. The most dominant year-to-year fluctuating pattern in Earth's climate system, El Niños have a powerful impact on the ocean and atmosphere, as well as important socioeconomic consequences. They can influence global weather patterns and the occurrence and frequency of hurricanes, droughts and floods; and can even raise or lower global temperatures by as much as 0.2 degrees Celsius (0.4 degrees Fahrenheit).

During a "classic" El Niño episode, the normally strong easterly trade winds in the tropical eastern Pacific weaken. That weakening suppresses the normal upward movement of cold subsurface waters and allows warm surface water from the central Pacific to shift toward the Americas. In these situations, unusually warm surface water occupies much of the tropical Pacific, with the maximum ocean warming remaining in the eastern-equatorial Pacific.

Since the early 1990s, however, scientists have noted a new type of El Niño that has been occurring with greater frequency. Known variously as "central-Pacific El Niño," "warm-pool El Niño," "dateline El Niño" or "El Niño Modoki" (Japanese for "similar but different"), the maximum ocean warming from such El Niños is found in the central-equatorial, rather than eastern, Pacific. Such central Pacific El Niño events were observed in 1991-92, 1994-95, 2002-03, 2004-05 and 2009-10. A recent study found many climate models predict such events will become much more frequent under projected global warming scenarios.

Lee said further research is needed to evaluate the impacts of these increasingly intense El Niños and determine why these changes are occurring. "It is important to know if the increasing intensity and frequency of these central Pacific El Niños are due to natural variations in climate or to climate change caused by human-produced greenhouse gas emissions," he said.

Results of the study were published recently in Geophysical Research Letters.

For more information on El Niño, visit: http://sealevel.jpl.nasa.gov/.

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Warmest Year-to-Date Global Temperature on Record

Warmest Year-to-Date Global Temperature on Record

  10:49:00 AM    Science Lover

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The combined global land and ocean surface temperature made this July the second warmest on record, behind 1998, and the warmest averaged January-July on record. The global average land surface temperature for July and January-July was warmest on record. The global ocean surface temperature for July was the fifth warmest, and for January-July 2010 was the second warmest on record, behind 1998.

The global average land surface temperature for July and January-July was warmest on record. (Credit: NOAA)

The monthly analysis from NOAA's National Climatic Data Center, which is based on records going back to 1880, is part of the suite of climate services NOAA provides government, business and community leaders so they can make informed decisions.

Global Temperature Highlights 

• The combined global land and ocean average surface temperature for July 2010 was the second warmest on record at 61.6°F (16.5°C), which is 1.19°F (0.66°C) above the 20th century average of 60.4°F (15.8°C). The averaged temperature for July 1998 was 61.7°F (16.5°C). 

• The July worldwide land surface temperature was 1.85°F (1.03°C) above the 20th century average of 57.8°F (14.3°C) -- the warmest July on record. Warmer-than-average conditions dominated land areas of the globe. The most prominent warmth was in Europe, western Russia and eastern Asia. Cooler-than-average regions included central Russia, Alaska and southern South America.

• According to the Finnish Meteorological Institute, Finland set a new all-time maximum temperature on July 29 when temperatures soared to 99.0°F (37.2°C), surpassing the previous record set in July 1914 by 2.3°F (1.3°C).

• Western Russia was engulfed by a severe heat wave during much of July. On July 30, Moscow set a new all-time temperature record when temperatures reached 102°F (39°C), exceeding the previous record of 99.0°F (37.2°C) set four days earlier. Before 2010, the highest maximum temperature recorded in Moscow was 98.2°F (36.8°C), set nine decades ago.

• According to the Beijing Climate Center, the July 2010 average temperature across China was 73.0°F (22.8°C), which is 2.5°F (1.4°C) above the 1971-2000 average and the warmest July since 1961.

• The worldwide ocean surface temperature was 0.97°F (0.54°C) above the 20th century average of 61.5°F (16.4°C) and the fifth warmest July on record. The warmth was most pronounced in the Atlantic Ocean.

• La Niña conditions developed during July 2010, as sea surface temperatures (SST) continued to drop across the central and eastern equatorial Pacific Ocean. According to NOAA's Climate Prediction Center, La Niña is expected to strengthen and last through the Northern Hemisphere winter 2010-2011.

• For the year-to-date, the global combined land and ocean surface temperature of 58.1°F (14.5°C) was the warmest January-July period on record. This value is 1.22°F (0.68°C) above the 20th century average.

Polar Sea Ice and Precipitation Highlights

• Arctic sea ice covered an average of 3.2 million square miles (8.4 million square kilometers) during July. This is 16.9 percent below the 1979-2000 average extent and the second lowest July extent since records began in 1979. The record low July was set in 2007. This was the 14th consecutive July with below-average Arctic sea ice extent. July 1996 was the last year that had above-average sea ice extent.

• Antarctic sea ice extent in July was above average, 4.8 percent above the 1979-2000 average -- resulting in the largest July sea ice extent on record.

• According to Australia's Bureau of Meteorology, the continent received an average of 34.4 mm (1.35 inches) of precipitation during July 2010 -- this is 55 percent above the 1961-1990 average and the highest value since 1998.

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Global Tropical Forests Threatened by 2100

Global Tropical Forests Threatened by 2100

  1:02:00 AM    Science Lover

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By 2100 only 18% to 45% of the plants and animals making up ecosystems in global, humid tropical forests may remain as we know them today, according to a new study led by Greg Asner at the Carnegie Institution's Department of Global Ecology. The research combined new deforestation and selective logging data with climate-change projections. It is the first study to consider these combined effects for all humid tropical forest ecosystems and can help conservationists pinpoint where their efforts will be most effective. The study is published in the August 5, 2010, issue of Conservation Letters.

Tropical forests hold more then half of all the plants 
and animal species on Earth. But the combined effect of 
climate change, forest clear cutting, and logging may 
force them to adapt, move, or die. (Credit: 
iStockphoto/Sze Rei Wong)

"This is the first global compilation of projected ecosystem impacts for humid tropical forests affected by these combined forces," remarked Asner. "For those areas of the globe projected to suffer most from climate change, land managers could focus their efforts on reducing the pressure from deforestation, thereby helping species adjust to climate change, or enhancing their ability to move in time to keep pace with it. On the flip side, regions of the world where deforestation is projected to have fewer effects from climate change could be targeted for restoration."

Tropical forests hold more then half of all the plants and animal species on Earth. But the combined effect of climate change, forest clear cutting, and logging may force them to adapt, move, or die.

The scientists looked at land use and climate change by integrating global deforestation and logging maps from satellite imagery and high-resolution data with projected future vegetation changes from 16 different global climate models. They then ran scenarios on how different types of species could be geographically reshuffled by 2100.They used the reorganization of plant classes, such as tropical broadleaf evergreen trees, tropical drought deciduous trees, plus different kinds of grasses as surrogates for biodiversity changes.

For Central and South America, climate change could alter about two-thirds of the humid tropical forests biodiversity -- the variety and abundance of plants and animals in an ecosystem. Combining that scenario with current patterns of land-use change, and the Amazon Basin alone could see changes in biodiversity over 80% of the region.

Most of the changes in the Congo area likely to come from selective logging and climate change, which could negatively affect between 35% and 74% of that region. At the continental scale, about 70% of Africa's tropical forest biodiversity would likely be affected if current practices are not curtailed.

In Asia and the central and southern Pacific islands, deforestation and logging are the primary drivers of ecosystem changes. Model projections suggest that climate change might play a lesser role there than in Latin America or Africa. That said, the research showed that between 60% and 77% of the area is susceptible to biodiversity losses via massive ongoing land-use changes in the region.

"This study is the strongest evidence yet that the world's natural ecosystems will undergo profound changes -- including severe alterations in their species composition -- through the combined influence of climate change and land use," remarked Daniel Nepstad, senior scientist at the Woods Hole Research Center. "Conservation of the world's biota, as we know it, will depend upon rapid, steep declines in greenhouse gas emissions."

The John D. and Catherine T. MacArthur Foundation and the Gordon and Betty Moore Foundation, support the Carnegie Landsat Analysis System, the Global Spectronomics project, and this study.

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CO2: Missing Link to Past Climate Changes

CO2: Missing Link to Past Climate Changes

  8:15:00 PM    Science Lover

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Increasingly, the Earth's climate appears to be more connected than anyone would have imagined. El Nino, the weather pattern that originates in a patch of the equatorial Pacific, can spawn heat waves and droughts as far away as Africa.

Sedimentary cores taken from the ocean floor in four l
ocations show that climate patterns in the tropics have 
mirrored Ice Age cycles for the last 2.7 million years 
and that carbon dioxide has played the leading role in 
determining global climate patterns. Cores from site 806 
were used as controls. (Credit: Timothy Herbert, 
Brown University)

Now, a research team led by Brown University has established that the climate in the tropics over at least the last 2.7 million years changed in lockstep with the cyclical spread and retreat of ice sheets thousands of miles away in the Northern Hemisphere. The findings appear to cement the link between the recent Ice Ages and temperature changes in tropical oceans. Based on that new link, the scientists conclude that carbon dioxide has played the lead role in dictating global climate patterns, beginning with the Ice Ages and continuing today.

"We think we have the simplest explanation for the link between the Ice Ages and the tropics over that time and the apparent role of carbon dioxide in the intensification of Ice Ages and corresponding changes in the tropics," said Timothy Herbert, professor of geological sciences at Brown and the lead author of the paper in Science.

"It certainly supports the idea of global sensitivity of climate to carbon dioxide as the first order of control on global temperature patterns," Herbert added, "but we don't know why. The answer lies in the ocean, we're pretty sure."

The research team, including scientists from Luther College in Iowa, Lafayette College in Pennsylvania, and the University of Hong Kong, analyzed cores taken from the seabed at four locations in the tropical oceans: the Arabian Sea, the South China Sea, the eastern Pacific and the equatorial Atlantic Ocean.

They decided to zero in on tropical ocean surface temperatures because these vast bodies, which make up roughly half of the world's oceans, in large measure orchestrate the amount of water in the atmosphere and thus rainfall patterns worldwide, as well as the concentration of water vapor, the most prevalent greenhouse gas.

Looking at the chemical remains of tiny marine organisms that lived in the sunlit zone of the ocean, the scientists were able to extract the surface temperature for the oceans for the last 3.5 million years, well before the beginning of the Ice Ages. Beginning about 2.7 million years ago, the geologists found that tropical ocean surface temperatures dropped by 1 to 3 degrees Celsius (1.8 to 5.4 degrees Fahrenheit) during each Ice Age, when ice sheets spread in the Northern Hemisphere and significantly cooled oceans in the northern latitudes. Even more compelling, the tropics also changed when Ice Age cycles switched from roughly 41,000-year to 100,000-year intervals.

"The tropics are reproducing this pattern both in the cooling that accompanies the glaciation in the Northern Hemisphere and the timing of those changes," Herbert said. "The biggest surprise to us was how similar the patterns looked all across the tropics since about 2.7 million years ago. We didn't expect such similarity."

Climate scientists have a record of carbon dioxide levels for the last 800,000 years -- spanning the last seven Ice Ages -- from ice cores taken in Antarctica. They have deduced that carbon dioxide levels in the atmosphere fell by about 30 percent during each cycle, and that most of that carbon dioxide was absorbed by high-latitude oceans such as the North Atlantic and the Southern Ocean. According to the new findings, this pattern began 2.7 million years ago, and the amount of atmospheric carbon dioxide absorbed by the oceans has intensified with each successive Ice Age. Geologists know the Ice Ages have gotten progressively colder -- leading to larger ice sheets -- because they have found debris on the seabed of the North Atlantic and North Pacific left by icebergs that broke from the land-bound sheets.

"It seems likely that changes in carbon dioxide were the most important reason why tropical temperatures changed, along with the water vapor feedback," Herbert said.

Herbert acknowledges that the team's findings leave important questions. One is why carbon dioxide began to play a major role when the Ice Ages began 2.7 million years ago. Also left unanswered is why carbon dioxide appears to have magnified the intensity of successive Ice Ages from the beginning of the cycles to the present. The researchers do not understand why the timing of the Ice Age cycles shifted from roughly 41,000-year to 100,000-year intervals.

Contributing authors are Laura Cleaveland Peterson at Luther College, Kira Lawrence at Lafayette College and Zhonghui Liu at the University of Hong Kong. The U.S. National Science Foundation and the Evolving Earth Foundation funded the research. The cores came from the Ocean Drilling Program, sponsored by the NSF, and the Integrated Ocean Drilling Program.

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High-Yield Agriculture Slows Global Warming

High-Yield Agriculture Slows Global Warming

  1:17:00 AM    Science Lover

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Advances in high-yield agriculture over the latter part of the 20th century have prevented massive amounts of greenhouse gases from entering the atmosphere -- the equivalent of 590 billion metric tons of carbon dioxide -- according to a new study led by two Stanford Earth scientists.

Increased yields of crops -- such as this maize in Kenya -- 
have not only helped feed the world, but have reduced 
greenhouse gas emissions. (Credit: Marshall Burke)

The yield improvements reduced the need to convert forests to farmland, a process that typically involves burning of trees and other plants, which generates carbon dioxide and other greenhouse gases.

The researchers estimate that if not for increased yields, additional greenhouse gas emissions from clearing land for farming would have been equal to as much as a third of the world's total output of greenhouse gases since the dawn of the Industrial Revolution in 1850.

The researchers also calculated that for every dollar spent on agricultural research and development since 1961, emissions of the three principal greenhouse gases -- methane, nitrous oxide and carbon dioxide -- were reduced by the equivalent of about a quarter of a ton of carbon dioxide -- a high rate of financial return compared to other approaches to reducing the gases.

"Our results dispel the notion that modern intensive agriculture is inherently worse for the environment than a more 'old-fashioned' way of doing things," said Jennifer Burney, lead author of a paper describing the study that will be published online by the Proceedings of the National Academy of Sciences.

Adding up the impact

The researchers calculated emissions of carbon dioxide, methane and nitrous oxide, converting the amounts of the latter two gases into the quantities of carbon dioxide that would have an equivalent impact on the atmosphere, to facilitate comparison of total greenhouse gas outputs.

Burney, a postdoctoral researcher with the Program on Food Security and the Environment at Stanford, said agriculture currently accounts for about 12 percent of human-caused greenhouse gas emissions. Although greenhouse gas emissions from the production and use of fertilizer have increased with agricultural intensification, those emissions are far outstripped by the emissions that would have been generated in converting additional forest and grassland to farmland.

"Every time forest or shrub land is cleared for farming, the carbon that was tied up in the biomass is released and rapidly makes its way into the atmosphere -- usually by being burned," she said. "Yield intensification has lessened the pressure to clear land and reduced emissions by up to 13 billion tons of carbon dioxide a year."

"When we look at the costs of the research and development that went into these improvements, we find that funding agricultural research ranks among the cheapest ways to prevent greenhouse gas emissions," said Steven Davis, a co-author of the paper and a postdoctoral researcher at the Carnegie Institution at Stanford.

To evaluate the impact of yield intensification on climate change, the researchers compared actual agricultural production between 1961 and 2005 with hypothetical scenarios in which the world's increasing food needs were met by expanding the amount of farmland rather than by the boost in yields produced by the Green Revolution.

"Even without higher yields, population and food demand would likely have climbed to levels close to what they are today," said David Lobell, also a coauthor and assistant professor of environmental Earth system science at Stanford.

"Lower yields per acre would likely have meant more starvation and death, but the population would still have increased because of much higher birth rates," he said. "People tend to have more children when survival of those children is less certain."

Avoiding the need for more farmland

The researchers found that without the advances in high-yield agriculture, several billion additional acres of cropland would have been needed.

Comparing emissions in the theoretical scenarios with real-world emissions from 1961 to 2005, the researchers estimated that the actual improvements in crop yields probably kept greenhouse gas emissions equivalent to at least 317 billion tons of carbon dioxide out of the atmosphere, and perhaps as much as 590 billion tons.

Without the emission reductions from yield improvements, the total amount of greenhouse gas pumped into the atmosphere over the preceding 155 years would have been between 18 and 34 percent greater than it has been, they said.

To calculate how much money was spent on research for each ton of avoided emissions, the researchers calculated the total amount of agricultural research funding related to yield improvements since 1961 through 2005. That produced a price between approximately $4 and $7.50 for each ton of carbon dioxide that was not emitted.

"The size and cost-effectiveness of this carbon reduction is striking when compared with proposed mitigation options in other sectors," said Lobell. "For example, strategies proposed to reduce emissions related to construction would cut emissions by a little less than half the amount that we estimate has been achieved by yield improvements and would cost close to $20 per ton."

The authors also note that raising yields alone won't guarantee lower emissions from land use change.

"It has been shown in several contexts that yield gains alone do not necessarily stop expansion of cropland," Lobell said. "That suggests that intensification must be coupled with conservation and development efforts.

"In certain cases, when yields go up in an area, it increases the profitability of farming there and gives people more incentive to expand their farm. But in general, high yields keep prices low, which reduces the incentive to expand."

The researchers concluded that improvement of crop yields should be prominent among a portfolio of strategies to reduce global greenhouse gases emissions.

"The striking thing is that all of these climate benefits were not the explicit intention of historical investments in agriculture. This was simply a side benefit of efforts to feed the world," Burney noted. "If climate policy intentionally rewarded these kinds of efforts, that could make an even bigger difference. The question going forward is how climate policy might be designed to achieve that."

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Climate Change and Mountain Building Led to Mammal Diversity Patterns

Climate Change and Mountain Building Led to Mammal Diversity Patterns

  1:22:00 AM    Science Lover

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Travel from the tropics to the poles, and you'll notice that the diversity of mammals declines with distance from the equator. Move from lowland to mountains, and you'll see diversity increase as the landscape becomes more varied. Ecologists have proposed various explanations for these well-known "biodiversity gradients," invoking ecological, evolutionary and historical processes.

Golden-mantled ground squirrel in Utah mountains and fossil squirrel jaw document high rodent diversity in topographically complex western North America today and 16 Million years ago. (Credit: Squirrel photo by Catherine Badgley; Fossil rodent jaw photo by University of California Museum of Paleontology (photo used with permission); Topographic pattern from MyTopo (used with permission))

New findings by University of Michigan researchers John A. Finarelli and Catherine Badgley suggest that the elevational patterns of diversity we see today have appeared, disappeared and reappeared over Earth's history and that these patterns arise from interactions between climate change and mountain building.

The results, published online in the journal Proceedings of the Royal Society B, also have implications for conservation efforts in the face of modern-day global warming, said Finarelli, a visiting assistant professor in the Department of Geological Sciences.

In their study, focused on the Miocene Epoch, which began around 23 million years ago and ended about 5 million years ago, Finarelli and Badgley evaluated diversity for more than 400 rodent species from adjacent regions that differed in geologic history and topography. The geologically "active region," which extends from the Front Range of the Rocky Mountains to the Pacific coast, has experienced several episodes of mountain-building and volcanic activity, and as a result has a topographically complex landscape. In contrast, the relatively flat Great Plains, has been more stable geologically.

The prevailing notion has been that diversity is greater in mountainous regions than in lowlands simply because the topography is more complex. As mountains rise up, new habitats are created, and areas that once were continuous become fragmented. Such changes offer opportunities for new species to arise, increasing diversity.

But climate also enters in, the new study shows. During the Miocene, long-term, global cooling was interrupted by warm intervals. In the active region, diversity increased during a warm interval from 17 to 14 million years ago that coincided with intensified mountain building and volcanic activity, the analysis revealed. During subsequent cooling, diversity declined in the mountains and increased on the plains.

"This pattern suggests that the elevational diversity gradient arises during historical episodes associated with global warming and mountain building," said Badgley, an assistant professor in the Department of Ecology and Evolutionary Biology and a research scientist in the Museum of Paleontology and the Department of Geological Sciences. "This gradient is not a long-term feature of North American biodiversity."

Although the research focused on ancient ecosystems, the findings have implications for modern times, Finarelli said. "Based on our finding that more complex regions are more sensitive to climate change, threatened areas in mountainous regions should be a particular conservation concern, with respect to human-mediated climate change."

The work also highlights the importance of studies that merge the disciplines of paleontology and biogeography, Finarelli said. "By marrying the two subjects, we can gain a better insight into the ecological and evolutionary processes shaping the world around us."

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