Lower Increases In Global Temperatures Could Lead To Greater Impacts Than Previously Thought, Study Finds

Posted by Robert Dickinson on March 1, 2009 at 9:17am

Global average radiative forcing estimates and...

Lower Increases In Global Temperatures Could Lead To Greater Impacts Than Previously Thought, Study Finds

ScienceDaily (Mar. 1, 2009) — A new study by scientists updating some of the findings of the Intergovernmental Panel on Climate Change (IPCC) 2001 Third Assessment Report finds that even a lower level of increase in average global temperatures due to greenhouse gas emissions could cause significant problems in five key areas of global concern.

The study, published in theProceedings of the National Academy of Sciences, is titled "Assessing Dangerous Climate Change Through an Update of the IPCC 'Reasons for Concern."

In 2001, the IPCC published as part of its Third Assessment Report an illustrative figure which identified changes in climate authors determined to be "reasons for concern," and which could cause some or significant risks among five types of outcomes that could be categorized as "dangerous."

Sometimes referred to as the "burning embers" diagram, the five reasons for concern are:

Risk to unique and threatened systems, such as the potential for increased damage to or irreversible loss of unique and threatened systems such as coral reefs, tropical glaciers, endangered species, unique ecosystems, biodiversity hotspots, small island states, and indigenous communities. The study authors contend that there is new and stronger evidence since 2001 of observed impacts of climate change on unique and vulnerable systems, with increasing levels of adverse impacts as temperatures increase further.
Risk of extreme weather events, which tracks increases in extreme events with substantial consequences for societies and natural systems. Examples include increase in the frequency, intensity, or consequences of heat waves, floods, droughts, wildfires or tropical cyclones. The study authors point to new and stronger evidence of the likelihood and likely impacts of such changes, such as the IPCC Fourth Assessment Report conclusion that it is now "more likely than not" that human activity has contributed to observed increases in heat waves, intense precipitation events, and intensity of tropical cyclones.
Distribution of impacts, which concern disparities of impacts, i.e. whether the poor are more vulnerable than the wealthy. Some regions, countries, and populations face greater harm from climate change while other regions, countries, or populations would be much less harmed - and some may benefit. The researchers find, for example, there is increased evidence that low-latitude and less-developed areas generally face greater risk than higher latitude and more developed countries and there will likely be disparate impacts even for different groups within developed countries.
Aggregate damages, which covers comprehensive measures of impacts from climate change. Impacts distributed across the globe can be aggregated into a single metric such as monetary damages, lives affected, or lives lost. The study authors determine that it is likely there will be higher damages for increases in average global temperature then previously thought, and climate change over the next century will likely adversely impact hundreds of millions of people.
Risks of large-scale discontinuities, which represent the likelihood that certain phenomena (sometimes called singularities or tipping points) would occur, any of which may be accompanied by very large impacts, such as the melting of major ice sheets. There is now better understanding that the risk of additional contributions to sea level rise from melting of both the Greenland and possibly Antarctic ice sheets may be larger than projected by ice sheet models assessed in the AR4, and that several meters of additional sea level rise could occur on century time scales.

The United Nations Framework Convention on Climate Change, which is in force and which the United States has ratified, calls for "stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system." That level is not defined by the Convention nor has it been clearly defined in subsequent negotiations by parties to the Convention.

One of the authors, Michael Oppenheimer, a professor of geosciences and international affairs at Princeton University's Woodrow Wilson School, said, "The more we learn about the problem, the more severe the risk becomes and the nearer it looms. Cutting emissions of the greenhouse gases promptly is the surest way to reduce the risk, and that's how governments should be responding."

A lead author, Stephen H. Schneider, Stanford University professor of biology and interdisciplinary environmental studies and Senior Fellow at the Woods Institute for the Environment, said, "We need both mitigation and adaptation policies to cope with climate change, since we must adapt to changes we cannot prevent and mitigate changes that are hard to adapt to—that is, mitigation and adaptation are complements, not trade-offs"

Another lead author, Joel B. Smith, a Vice-President at Stratus Consulting in Boulder Colorado, said, "Based on observed impacts and new research, the risks from climate change in general now appear to be greater than they did a few years ago. The current path of greenhouse gas emissions is likely to lead to a change in climate that will exceed levels which we found will cause significant adverse impacts."

Other co-authors pf the study are Gary W. Yohe, William Hare, Michael D. Mastrandrea, Anand Patwardhan, Ian Burton, Jan Corfee-Morlot, Chris. H. D. Magadza, Hans-Martin Füssel, A. Barrie Pittock, Atiq Rahman, Avelino Suarez, and Jean-Pascal van Ypersele.

Journal reference:

Joel B. Smith, Stephen H. Schneider, Michael Oppenheimer, Gary W. Yohe, William Hare, Michael D. Mastrandrea, Anand Patwardhan, Ian Burton, Jan Corfee-Morlot, Chris H. D. Magadza, Hans-Martin Füssel, A. Barrie Pittock, Atiq Rahman, Avelino Suarez, and Jean-Pascal van Ypersele. Assessing dangerous climate change through an update of the Intergovernmental Panel on Climate Change (IPCC) "reasons for concern". Proceedings of the National Academy of Sciences, 2009; DOI:10.1073/pnas.0812355106

Adapted from materials provided by Stanford University, viaEurekAlert!, a service of AAAS.

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Thunder, Hail, Fire: What Does Climate Change Mean for the U.S.?

Posted by Robert Dickinson on February 19, 2009 at 11:00am

The antarctic is melting w002n54 84m sea level...

Image by pyrator via Flickr

News - December 5, 2007

Thunder, Hail, Fire: What Does Climate Change Mean for the U.S.?

The regional effects range from more wildfires in the west to stronger storms in the east.

By David Biello

The U.S. heartland can look forward to hotter, wetter summers, according to the latest climate research. Global warming will cause more severe thunderstorms—convective cloud fronts that could produce wind gusts of 58 miles (93 kilometers) per hour, 0.75-inch (1.9-centimeter) size hailstones and even more frequent tornadoes—in the region, according to research led by atmospheric scientist Robert Trapp at Purdue University. At the same time, according to independent environmental consultant Kristie Ebi, heat waves like the one in Chicago that killed 700 people in 1995 will become more commonplace.

"Climate change is projected to increase the frequency, intensity and duration of heat waves in the Midwest," says Ebi, an Intergovernmental Panel on Climate Change (IPCC) report author. "In addition, heat waves are projected to be hotter."

Of course, the U.S. Midwest is not the only region of the world that is being affected by climate change. Signs of global warming are beginning to appear everywhere: from runaway ice melt in the Arctic to slowly drowning islands in the Pacific. "Changing climate conditions are already happening," says Eileen Claussen, president of the Pew Center on Global Climate Change, which today released a report on regional impacts in the U.S. "It is clear that there is an immediate need for strong national and international policy action."

The reports findings, in addition to increased heat waves, include:

Western Wildfires—The increasingly destructive and widespread fire seasons of recent years are likely to continue due to a combination of increased drought and land development encroaching on naturally burning landscapes, along with a climate change–induced fuel boom (enhanced plant growth and a shift to more woody species) exacerbated by fire-suppression efforts leading to more abundant plant matter to fuel violent blazes, according to ecologist Dominique Bachelet of Oregon State University in Corvallis and The Nature Conservancy. "The deadly combination of human behavior and climate change means we will likely see more wildfires like those in 2007," she says.

Gulf Coast Swamped—Human engineering efforts such as levees have reduced the ability of the wetlands of Louisiana and other Gulf Coast states to keep pace with subsiding land and rising sea levels, according to coastal scientist Robert Twilley of Louisiana State University in Baton Rouge. "If soil formation cannot keep pace," he says, "inundation of wetlands from rising seas will essentially drown these landscapes, and wetlands will convert to open waters." That, in turn, will make nearby communities far more vulnerable to the effects of storm surges, such as the one caused by Hurricane Katrina in 2005.

"Dead Zones" Deader—One of a number of large and growing seasonal areas in bodies of water from which all oxygen has been leeched drives the degradation of Chesapeake Bay. A "dead zone" is a place devoid of the fish and bottom dwellers, such as the crabs and other shellfish, for which the bay is famous. Marine scientist Donald Boesch, president of the University of Maryland Center for Environmental Science, warns that climate change will also complicate the already difficult task of restoring this important watershed and food source. "Climate change impacts are not straightforward," he says, "but are multiple and interactive."

And the Pew report is not the only research to examine regional impacts.

Stronger Storms—Much of the country will experience severe thunderstorms, but major eastern and southeastern cities are likely to see the largest jumps in storm frequency, according to Purdue's Trapp—a finding buttressed by a NASA study earlier this year. "Our analysis suggests the possibility of an increase of up to 100 percent or more in locations such as Atlanta and New York," the researchers wrote in this week's Proceedings of the National Academy of Sciences.

As a result, these experts say efforts to combat climate change must focus not only on reducing greenhouse gas emissions that drive global warming but also on adjusting to the changes already underway. "The challenge we have with adaptation is trying to understand the specific impacts of climate change on a region," Boesch says. Nevertheless, "adaptation is going to be essential because we cannot avoid climate change entirely."

100-Year Forecast: New Climate Zones Humans Have Never Seen Worst-case warming scenario may bring totally new kinds of tropical climate and cause others to disappear By JR Minkel If global warming continues unabated, many of the world's climate zones may disappear by 2100, leaving new ones in their place unlike any that exist today, according to a new study. Researchers compared existing patterns of temperature and precipitation with those that may exist at the turn of the century, based on scenarios put forth in the recent report of the Intergovernmental Panel on Climate Change (IPCC). They found that if greenhouse gas emissions continue rising at the same rate, up to 39 percent of Earth's continental surface may experience totally new climates, primarily in the tropics and adjacent latitudes as warmer temperatures spread toward the poles. Researchers say the analysis was intended to more precisely gauge the ecological consequences of climate change. Studies have already estimated that species such as butterflies are creeping toward the poles at a rate of six kilometers per decade as temperatures rise. Some species, however, may not be able to keep pace with future changes potentially leading to new regional ecosystems as novel climate patterns emerge, possibly leading to extinctions if some climates disappear entirely. To evaluate the range of possible outcomes, ecologists John Williams of the University of Wisconsin–Madison, and Stephen Jackson of the University of Wyoming, along with U.W. Madison climatologist John Kutzbach compared global climate projections published last month by the fourth IPCC with current regional climates, looking specifically at average summer and winter temperatures and precipitation. They considered scenarios of either unchecked greenhouse gas emissions or a global reduction in the rate of emissions growth. They found that the business-as-usual scenario comes with large climate changes the world over and would create entirely new patterns of temperature and precipitation for 12 to 39 percent of Earth's land area. An additional 10 to 48 percent of land would see its climate zones disappear, replaced by patterns of temperature and precipitation now occurring elsewhere, such as rain forest becoming savanna or evergreen forest becoming deciduous. In the reduced-emissions scenario, the group reports that the two kinds of change would each take hold over 4 to 20 percent of land. In the case of unchecked emissions, "we are going to be seeing climates that certainly are completely outside the range of modern human experience," Jackson says. According to the analysis, new climates would be most dramatic in the rain forests of the Amazon and Indonesia, but would extend as far toward the poles as the American southeast. Climate disappearance would occur in tropical mountains and near the poles, including regions such as the Andes, the African highlands, Indonesia and the Philippines, parts of the Himalayas and near the Arctic. With nowhere to go, species in these regions might become extinct, the group notes in this week's Proceedings of the National Academy of Sciences USA. Jackson says that prior studies have concentrated on ecological changes closer to the poles, but the tropical changes might be more dramatic. "If [the climate of] Memphis moves to Chicago, we have a Memphis there to say what Chicago will look like," he says. "For an area where we don't have a modern analogue, there's really nothing to look at to say, this is what the environment will look like."

Source: http://www.sciam.com/article.cfm?id=100-year-forecast-new-cli

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