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20 October 2008 at 12:05 pm #3516
News from WWF UK:Quote:Global warming is accelerating at a faster rate than climate change experts previously predicted, according to a new summary of scientific research released today by WWF. The findings add further weight to our call for the EU to commit to real emissions cuts within Europe.
WWF’s report brings together new scientific data that has emerged since the Nobel Prize-winning Intergovernmental Panel on Climate Change (IPCC) released its Fourth Assessment Report last year.
The new report, Climate change: faster, stronger, sooner, reveals that global warming is accelerating beyond the IPCC’s forecasts:
- The Arctic Ocean is losing sea ice up to 30 years ahead of IPCC predictions. It is now predicted that the summer sea ice could completely disappear between 2013 and 2040 – something that hasn’t occurred in more than a million years.
- Global sea level rise is expected to reach more than double the IPCC’s maximum estimate of 0.59m by the end of the century, putting vast coastal areas at risk.
- Natural carbon sinks – the areas that help to absorb CO2 from the atmosphere – are losing their ability to soak up growing levels of emissions faster than expected.
- Rising temperatures have already led to a major reduction in global yields of wheat, maize and barley, resulting in losses of 40 million tonnes of grain per year.
- Marine ecosystems in the North and Baltic Sea are being exposed to the warmest temperatures measured since records began.
- The number and intensity of extreme cyclones over the British Isles and the North Sea are projected to increase, leading to increased wind speeds and storm-related losses over Western and Central Europe.
…27 December 2008 at 1:41 pm #4568
New report from US Geological Survey likewise indicates climate change is more urgent than had been widely anticipated. Press release:Quote:The United States faces the potential for abrupt climate change in the 21st century that could pose clear risks to society in terms of our ability to adapt.
"Abrupt" changes can occur over decades or less, persist for decades more, and cause substantial disruptions to human and natural systems.
A new report, based on an assessment of published science literature, makes the following conclusions about the potential for abrupt climate changes from global warming during this century.
- Climate model simulations and observations suggest that rapid and sustained September arctic sea ice loss is likely in the 21st century.
- The southwestern United States may be beginning an abrupt period of increased drought.
- It is very likely that the northward flow of warm water in the upper layers of the Atlantic Ocean, which has an important impact on the global climate system, will decrease by approximately 25-30 percent. However, it is very unlikely that this circulation will collapse or that the weakening will occur abruptly during the 21st century and beyond.
- An abrupt change in sea level is possible, but predictions are highly uncertain due to shortcomings in existing climate models.
- There is unlikely to be an abrupt release of methane, a powerful greenhouse gas, to the atmosphere from deposits in the earth. However, it is very likely that the pace of methane emissions will increase.
The U.S. Geological Survey led the new assessment, which was authored by a team of climate scientists from the federal government and academia. The report was commissioned by the U.S. Climate Change Science Program with contributions from the National Oceanic and Atmospheric Administration and the National Science Foundation.
"This report was truly a collaborative effort between world renowned scientists who provided objective, unbiased information that is necessary to develop effective adaptation and mitigation strategies that protect our livelihood," said USGS Director Mark Myers. "It summarizes the scientific community’s growing understanding regarding the potential for abrupt climate changes and identifies areas for additional research to further improve climate models."
Further research is needed to improve our understanding of the potential for abrupt changes in climate. For example, the report’s scientists found that processes such as interaction of warm ocean waters with the periphery of ice sheets and ice shelves have a greater impact than previously known on the destabilization of ice sheets that might accelerate sea-level rise.
To view the full report, titled Synthesis and Assessment Product 3.4: Abrupt Climate Change, and a summary brochure on abrupt climate change, visit http://www.climatescience.gov/default.php.
Abrupt Climate Change: Will It Happen this Century?15 February 2009 at 10:50 am #4587
From BBC news:Quote:
The severity of global warming over the next century will be much worse than previously believed, a leading climate scientist has warned.
Professor Chris Field, an author of a 2007 landmark report on climate change, said future temperatures "will be beyond anything" predicted.
Prof Field said the Intergovernmental Panel on Climate Change (IPCC) report had underestimated the rate of change.
He said warming is likely to cause more environmental damage than forecast.
Speaking at the American Science conference in Chicago, Prof Field said fresh data showed greenhouse gas emissions between 2000 and 2007 increased far more rapidly than expected.
"We are basically looking now at a future climate that is beyond anything that we’ve considered seriously in climate policy," he said.8 April 2009 at 12:27 am #4602
From Reuters:Quote:Global warming is likely to overshoot a 2 degrees Celsius (3.6 F) rise seen by the European Union and many developing nations as a trigger for "dangerous" change, a Reuters poll of scientists showed on Tuesday.
Nine of 11 experts, who were among authors of the final summary by the U.N.’s Intergovernmental Panel on Climate Change in 2007 (IPCC), also said the evidence that mankind was to blame for climate change had grown stronger in the past two years.
Giving personal views of recent research, most projected on average a faster melt of summer ice in the Arctic and a quicker rise in sea levels than estimated in the 2007 report, the most authoritative overview to date drawing on work by 2,500 experts.
"A lot of the impacts we’re seeing are running ahead of our expectations," said William Hare of the Potsdam Institute for Climate Impact Research.
Ten of 11 experts said it was at best "unlikely" — or less than a one-third chance — that the world would manage to limit warming to a 2 degrees Celsius (3.6 Fahrenheit) rise above pre-industrial levels.
Six of the scientists said world average annual temperatures would set a new record by 2015 — and another four projected that it would happen by 2020 — dismissing views from skeptics that global warming has stopped.
The hottest year since records began in the 19th century was 1998, according to the World Meteorological Organization.
And the scientists generally said that sea levels would rise faster than projected in the IPCC report, in a threat to many cities, islands and coasts from Bangladesh to Florida.
The IPCC said seas would rise by between 18 and 59 cms (7-24 inches) this century. But it pointed to big uncertainties about ice sheets in Greenland or Antarctica — one IPCC estimate was that this ice could add up to 20 cms to sea level rise.
In the poll, the lowest projection for sea level rise by 2100 was 30-40 cms, the highest up to 140 cms.
And 10 of those polled projected that Arctic late summer sea ice could vanish before 2050, with two saying it could disappear by 2020. The IPCC had said some scenarios pointed to a loss in the latter half of the century.20 May 2009 at 1:09 am #4613
The most comprehensive modeling yet carried out on the likelihood of how much hotter the Earth’s climate will get in this century shows that without rapid and massive action, the problem will be about twice as severe as previously estimated six years ago – and could be even worse than that.
The study uses the MIT Integrated Global Systems Model, a detailed computer simulation of global economic activity and climate processes that has been developed and refined by the Joint Program on the Science and Policy of Global Change since the early 1990s. The new research involved 400 runs of the model with each run using slight variations in input parameters, selected so that each run has about an equal probability of being correct based on present observations and knowledge. Other research groups have estimated the probabilities of various outcomes, based on variations in the physical response of the climate system itself. But the MIT model is the only one that interactively includes detailed treatment of possible changes in human activities as well – such as the degree of economic growth, with its associated energy use, in different countries.
Study co-author Ronald Prinn, the co-director of the Joint Program and director of MIT’s Center for Global Change Science, says that, regarding global warming, it is important "to base our opinions and policies on the peer-reviewed science," he says. And in the peer-reviewed literature, the MIT model, unlike any other, looks in great detail at the effects of economic activity coupled with the effects of atmospheric, oceanic and biological systems. "In that sense, our work is unique," he says.
The new projections, published this month in the American Meteorological Society’s Journal of Climate, indicate a median probability of surface warming of 5.2 degrees Celsius by 2100, with a 90% probability range of 3.5 to 7.4 degrees. This can be compared to a median projected increase in the 2003 study of just 2.4 degrees. The difference is caused by several factors rather than any single big change. Among these are improved economic modeling and newer economic data showing less chance of low emissions than had been projected in the earlier scenarios. Other changes include accounting for the past masking of underlying warming by the cooling induced by 20th century volcanoes, and for emissions of soot, which can add to the warming effect. In addition, measurements of deep ocean temperature rises, which enable estimates of how fast heat and carbon dioxide are removed from the atmosphere and transferred to the ocean depths, imply lower transfer rates than previously estimated.
Prinn says these and a variety of other changes based on new measurements and new analyses changed the odds on what could be expected in this century in the "no policy" scenarios – that is, where there are no policies in place that specifically induce reductions in greenhouse gas emissions. Overall, the changes "unfortunately largely summed up all in the same direction," he says. "Overall, they stacked up so they caused more projected global warming."
While the outcomes in the "no policy" projections now look much worse than before, there is less change from previous work in the projected outcomes if strong policies are put in place now to drastically curb greenhouse gas emissions. Without action, "there is significantly more risk than we previously estimated," Prinn says. "This increases the urgency for significant policy action."
To illustrate the range of probabilities revealed by the 400 simulations, Prinn and the team produced a "roulette wheel" that reflects the latest relative odds of various levels of temperature rise. The wheel provides a very graphic representation of just how serious the potential climate impacts are.
"There’s no way the world can or should take these risks," Prinn says. And the odds indicated by this modeling may actually understate the problem, because the model does not fully incorporate other positive feedbacks that can occur, for example, if increased temperatures caused a large-scale melting of permafrost in arctic regions and subsequent release of large quantities of methane, a very potent greenhouse gas. Including that feedback "is just going to make it worse," Prinn says.
The lead author of the paper describing the new projections is Andrei Sokolov, research scientist in the Joint Program. Other authors, besides Sokolov and Prinn, include Peter H. Stone, Chris E. Forest, Sergey Paltsev, Adam Schlosser, Stephanie Dutkiewicz, John Reilly, Marcus Sarofim, Chien Wang and Henry D. Jacoby, all of the MIT Joint Program on the Science and Policy of Global Change, as well as Mort Webster of MIT’s Engineering Systems Division and D. Kicklighter, B. Felzer and J. Melillo of the Marine Biological Laboratory at Woods Hole.
Prinn stresses that the computer models are built to match the known conditions, processes and past history of the relevant human and natural systems, and the researchers are therefore dependent on the accuracy of this current knowledge. Beyond this, "we do the research, and let the results fall where they may," he says. Since there are so many uncertainties, especially with regard to what human beings will choose to do and how large the climate response will be, "we don’t pretend we can do it accurately. Instead, we do these 400 runs and look at the spread of the odds."
Because vehicles last for years, and buildings and powerplants last for decades, it is essential to start making major changes through adoption of significant national and international policies as soon as possible, Prinn says. "The least-cost option to lower the risk is to start now and steadily transform the global energy system over the coming decades to low or zero greenhouse gas-emitting technologies."
Climate change odds much worse than thought
New analysis shows warming could be double previous estimates4 September 2009 at 3:37 am #4637
From BBC News:Quote:
Arctic temperatures are now higher than at any time in the last 2,000 years, research reveals.
Changes to the Earth’s orbit drove centuries of cooling, but temperatures rose fast in the last 100 years as human greenhouse gas emissions rose.
Scientists took evidence from ice cores, tree rings and lake sediments.
Writing in the journal Science, they say this confirms that the Arctic is very sensitive both to changes in solar heating and to greenhouse warming.
The 23 sites sampled were good enough to provide a decade-by-decade picture of temperatures across the region.
The recent warming of the Arctic has manifested itself most clearly in the drastic shrinkage in summer sea-ice extent, with the smallest area in the satellite era documented in 2007.
As the Science study emerged, UN Secretary-General Ban Ki-moon was telling the World Climate Conference in Geneva that many of the "more distant scenarios" forecast by climate scientists were "happening now".
Earlier this week, Mr Ban visited the Arctic in an attempt to gain first-hand experience of how the region is changing.
"Scientists have been accused for years of scaremongering. But the real scaremongers are those who say we cannot afford climate action," he said in his Geneva speech, calling for world leaders to make bigger pledges of action in the run-up to December’s UN climate summit in Copenhagen.25 September 2009 at 1:52 am #4649
Press release from United Nations Environment Program:Quote:Washington/Nairobi, 24 September 2009 -The pace and scale of climate change may now be outstripping even the most sobering predictions of the last report of the Intergovernmental Panel of Climate Change (IPCC).
An analysis of the very latest, peer-reviewed science indicates that many predictions at the upper end of the IPCC’s forecasts are becoming ever more likely.
Meanwhile, the newly emerging science points to some events thought likely to occur in longer-term time horizons, as already happening or set to happen far sooner than had previously been thought.
Researchers have become increasingly concerned about ocean acidification linked with the absorption of carbon dioxide in seawater and the impact on shellfish and coral reefs.
? Water that can corrode a shell-making substance called aragonite is already welling up along the California coast?decades earlier than existing models predict.
Losses from glaciers, ice-sheets and the Polar Regions appear to be happening faster than anticipated, with the Greenland ice sheet, for example, recently seeing melting some 60 percent higher than the previous record of 1998.
? Some scientists are now warning that sea levels could rise by up to two metres by 2100 and five to ten times that over following centuries.
There is also growing concern among some scientists that thresholds or tipping points may now be reached in a matter of years or a few decades including dramatic changes to the Indian sub-continent’s monsoon, the Sahara and West Africa monsoons, and climate systems affecting a critical ecosystem like the Amazon rainforest.
The report also underlines concern by scientists that the planet is now committed to some damaging and irreversible impacts as a result of the greenhouse gases already in the atmosphere.
? Losses of tropical and temperate mountain glaciers affecting perhaps 20 percent to 25 percent of the human population in terms of drinking water, irrigation and hydro-power.
? Shifts in the hydrological cycle resulting in the disappearance of regional climates with related losses of ecosystems, species and the spread of drylands northwards and southwards away from the equator.
Recent science suggests that it may still be possible to avoid the most catastrophic impacts of climate change. However, this will only happen if there is immediate, cohesive and decisive action to both cut emissions and assist vulnerable countries adapt.
These are among the findings of a report released today by the United Nations Environment Programme (UNEP) entitled Climate Change Science Compendium 2009.
The report, compiled in association with scientists around the world, comes with less than 80 days to go to the crucial UN climate convention meeting in Copenhagen, Denmark.
In a foreword to the document, the United Nations Secretary-General, Ban Ki-moon, who this week hosted heads of state in New York, writes, "This Climate Change Science Compendium is a wake-up call. The time for hesitation is over".
"We need the world to realize, once and for all, that the time to act is now and we must work together to address this monumental challenge. This is the moral challenge of our generation."
The Compendium reviews some 400 major scientific contributions to our understanding of Earth Systems and climate change that have been released through peer-reviewed literature, or from research institutions, over the last three years.
Achim Steiner, UN Under-Secretary General and UNEP Executive Director, said, "The Compendium can never replace the painstaking rigour of an IPCC process?a shining example of how the United Nations can provide a path to consensus among the sometimes differing views of more than 190 nations".
"However, scientific knowledge on climate change and forecasting of the likely impacts has been advancing rapidly since the landmark 2007 IPCC report," he added.
"Many governments have asked to be kept abreast of the latest findings. I am sure that this report fulfils that request and will inform ministers’ decisions when they meet in the Danish capital in only a few weeks time," said Mr. Steiner.
The research findings and observations in the Compendium are divided into five categories: Earth Systems, Ice, Oceans, Ecosystems and Management. Key developments documented since the IPCC Fourth Assessment Report include:
? A new climate modeling system, forecasting average temperatures over a decade by combining natural variation with the impacts of human-induced climate change, projects that at least half of the 10 years following 2009 will exceed the warmest year currently on record. This is despite the fact that natural variation will partially offset the warming "signal" from greenhouse gas emissions.
? The growth in carbon dioxide emissions from energy and industry has exceeded even the most fossil-fuel intensive scenario developed by the IPCC at the end of the 1990s. Global emissions were growing by 1.1 percent each year from 1990-1999 and this accelerated to 3.5 percent per year from 2000-2007.
? The developing and least-developed economies, 80 percent of the world’s population, accounted for 73 percent of the global growth of emissions in 2004. However, they contributed only 41 percent of total emissions, and just 23 percent of cumulative emissions since 1750.
? Growth of the global economy in the early 2000s and an increase in its carbon intensity (emissions per unit of growth), combined with a decrease in the capacity of ecosystems on land and the oceans to act as carbon "sinks", have led to a rapid increase in the concentrations of carbon dioxide in the atmosphere. This has contributed to sooner-than-expected impacts including faster sea-level rise, ocean acidification, melting Arctic sea ice, warming of polar land masses, freshening of ocean currents and shifts in the circulation patterns of the oceans and atmosphere.
? The observed increase in greenhouse gas concentrations are raising concern among some scientists that warming of between 1.4 and 4.3 degrees Centigrade above pre-industrial surface temperatures could occur. This exceeds the range of between 1 and 3 degrees perceived as the threshold for many "tipping points", including the end of summer Arctic sea ice, and the eventual melting of Himalayan glaciers and the Greenland ice sheet.
? The melting of mountain glaciers appears to be accelerating, threatening the livelihoods of one fifth or more of the population who depend on glacier ice and seasonal snow for their water supply. For 30 reference glaciers in nine mountain ranges tracked by the World Glacier Monitoring Service, the mean rate of loss since 2000 has roughly doubled since the rate during the previous two decades. Current trends suggest that most glaciers will disappear from the Pyrenees by 2050 and from the mountains of tropical Africa by 2030.
? In 2007, summer sea ice in the Arctic Ocean shrank to its smallest extent ever, 24 percent less than the previous record in 2005, and 34 percent less than the average minimum extent in the period 1970-2000. In 2008, the minimum ice extent was 9 percent greater than in 2007, but still the second lowest on record.
? Until the summer of 2007, most models projected an ice-free September for the Arctic Ocean towards the end of the current century. Reconsideration based on current trends has led to speculation that this could occur as soon as 2030.
? Melting of the Greenland Ice Sheet surface also seems to be accelerating. In the summer of 2007, the rate of melting was some 60 percent higher than the previous record in 1998.
? The loss of ice from West Antarctica is estimated to have increased by 60 per cent in the decade to 2006, and by 140 percent from the Antarctic Peninsula in the same period.
? Recent findings show that warming extends well to the south of the Antarctic Peninsula, to cover most of West Antarctica, an area of warming much larger than previously reported.
? The hole in the ozone layer has had a cooling effect on Antarctica, and is partly responsible for masking expected warming on the continent. Recovery of stratospheric ozone, thanks to the phasing out of ozone-depleting substances, is projected to increase Antarctic temperatures in coming decades.
? Recent estimates of the combined impact of melting land-ice and thermal expansion of the oceans suggest a plausible average sea level rise of between 0.8 and 2.0 metres above the 1990 level by 2100. This compares with a projected rise of between 18 and 59 centimetres in the last IPCC report, which did not include an estimate of large-scale changes in ice-melt rates, due to lack of consensus.
? Oceans are becoming more acidic more quickly than expected, jeopardizing the ability of shellfish and corals to form their external skeletons. Water that can corrode a shell-making carbonate substance called aragonite is already welling up during the summer along the California coast, decades earlier than models predict.
? Since the 2007 IPCC report, wide-ranging surveys have shown changes to the seasonal behaviour and distribution of all well-studied marine, freshwater and terrestrial groups of plants and animals. Polar and mountaintop species have seen severe contractions of their ranges.
? A recent study projecting the impacts of climate change on the pattern of marine biodiversity suggests dramatic changes to come. Ecosystems in sub-polar waters, the tropics and semi-enclosed seas are predicted to suffer numerous extinctions by 2050, while the Arctic and Southern Oceans will experience severe species invasions. Marine ecosystems as a whole may see a species turnover of up to 60 percent.
? Under the IPCC scenario that most closely matches current trends ? i.e. with the highest projected emissions ? between 12 and 39 percent of the Earth’s land surface could experience previously unknown climate conditions by 2100. A similar proportion, between 10 and 48 percent, will see existing climates disappear. Many of these "disappearing climates" coincide with biodiversity hotspots, and with the added problem of fragmented habitats and physical obstructions to migration, it is feared many species will struggle to adapt to the new conditions.
? Perennial drought conditions have already been observed in South-eastern Australia and South-western North America. Projections suggest that persistent water scarcity will increase in a number of regions in coming years, including southern and northern Africa, the Mediterranean, much of the Middle East, a broad band in Central Asia and the Indian subcontinent.
? The reality of a rapidly-changing climate may make conventional approaches to conservation and restoration of habitats ineffective. Drastic measures such as large-scale translocation or assisted colonization of species may need to be considered.
? Eco-agriculture, in which landscapes are managed to sustain a range of ecosystem services, including food production, may need to replace the current segregation of land use between conservation and production. This could help create resilient agricultural ecosystems better able to adapt to the changing climate conditions.
? Experts increasingly agree that active protection of tropical forests is a cost-effective means of cutting global emissions. An international mechanism of reducing emissions from deforestation and forest degradation (REDD) is likely to emerge as a central component of a new agreement in Copenhagen. However, many issues need to be resolved, such as how to verify the reductions and ensuring fair treatment of local and indigenous forest communities.
? A number of innovative approaches are emerging to keep carbon out of the atmosphere, including the use of "biochar", biologically-derived charcoal. It is mixed in soils, increasing fertility and potentially locking up carbon for centuries. This is a 21st century application of a technology known as Terra Preta, or Black Earth, used by Amazon peoples before the arrival of Europeans in South America.
To download the full report, visit http://www.unep.org/compendium2009/28 September 2009 at 8:51 am #4653
From the Guardian:Quote:Unchecked global warming could bring a severe temperature rise of 4C within many people’s lifetimes, according to a new report for the British government that significantly raises the stakes over climate change.
The study, prepared for the Department of Energy and Climate Change by scientists at the Met Office, challenges the assumption that severe warming will be a threat only for future generations, and warns that a catastrophic 4C rise in temperature could happen by 2060 without strong action on emissions.
"We’ve always talked about these very severe impacts only affecting future generations, but people alive today could live to see a 4C rise," said Richard Betts, the head of climate impacts at the Met Office Hadley Centre, who will announce the findings today at a conference at Oxford University. "People will say it’s an extreme scenario, and it is an extreme scenario, but it’s also a plausible scenario.
Met Office warns of catastrophic global warming in our lifetimes23 November 2009 at 7:04 am #4661
From Associated Press:Quote:Since the 1997 international accord to fight global warming, climate change has worsened and accelerated — beyond some of the grimmest of warnings made back then.
As the world has talked for a dozen years about what to do next, new ship passages opened through the once frozen summer sea ice of the Arctic. In Greenland and Antarctica, ice sheets have lost trillions of tons of ice. Mountain glaciers in Europe, South America, Asia and Africa are shrinking faster than before.
And it’s not just the frozen parts of the world that have felt the heat in the dozen years leading up to next month’s climate summit in Copenhagen:
_ The world’s oceans have risen by about an inch and a half.
_Droughts and wildfires have turned more severe worldwide, from the U.S. West to Australia to the Sahel desert of North Africa.
_Species now in trouble because of changing climate include, not just the lumbering polar bear which has become a symbol of global warming, but also fragile butterflies, colorful frogs and entire stands of North American pine forests.
_Temperatures over the past 12 years are 0.4 of a degree warmer than the dozen years leading up to 1997.
Even the gloomiest climate models back in the 1990s didn’t forecast results quite this bad so fast.
"The latest science is telling us we are in more trouble than we thought," Janos Pasztor, climate adviser to UN Secretary General Ban Ki-moon.
"The message on the science is that we know a lot more than we did in 1997 and it’s all negative," said Eileen Claussen, president of the Pew Center on Global Climate Change. "Things are much worse than the models predicted."29 November 2009 at 2:09 am #4662
Press release on Copenhagen Diagnosis website:Quote:Global ice-sheets are melting at an increased rate; Arctic sea-ice is disappearing much faster than recently projected, and future sea-level rise is now expected to be much higher than previously forecast, according to a new global scientific synthesis prepared by some of the world’s top climate scientists.
In a special report called ‘The Copenhagen Diagnosis’, the 26 researchers, most of whom are authors of published IPCC reports, conclude that several important aspects of climate change are occurring at the high end or even beyond the expectations of only a few years ago.
The report also notes that global warming continues to track early IPCC projections based on greenhouse gas increases. Without significant mitigation, the report says global mean warming could reach as high as 7 degrees Celsius by 2100.
The Copenhagen Diagnosis, which was a year in the making, documents the key findings in climate change science since the publication of the landmark Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report in 2007.
The new evidence to have emerged includes:
- Satellite and direct measurements now demonstrate that both the Greenland and Antarctic ice-sheets are losing mass and contributing to sea level rise at an increasing rate.
- Arctic sea-ice has melted far beyond the expectations of climate models. For example, the area of summer sea-ice melt during 2007-2009 was about 40% greater than the average projection from the 2007 IPCC Fourth Assessment Report.
- Sea level has risen more than 5 centimeters over the past 15 years, about 80% higher than IPCC projections from 2001. Accounting for ice-sheets and glaciers, global sea-level rise may exceed 1 meter by 2100, with a rise of up to 2 meters considered an upper limit by this time. This is much higher than previously projected by the IPCC. Furthermore, beyond 2100, sea level rise of several meters must be expected over the next few centuries.
- In 2008 carbon dioxide emissions from fossil fuels were ~40% higher than those in 1990. Even if emissions do not grow beyond today’s levels, within just 20 years the world will have used up the allowable emissions to have a reasonable chance of limiting warming to less than 2 degrees Celsius.
The report concludes that global emissions must peak then decline rapidly within the next five to ten years for the world to have a reasonable chance of avoiding the very worst impacts of climate change.
To stabilize climate, global emissions of carbon dioxide and other long-lived greenhouse gases need to reach near-zero well within this century, the report states.
The full report is available at download.copenhagendiagnosis.org
Statements by Authors
"Sea level is rising much faster and Arctic sea ice cover shrinking more rapidly than we previously expected. Unfortunately, the data now show us that we have underestimated the climate crisis in the past."
Professor Stefan Rahmstorf, Professor of Physics of the Oceans and a Department Head at the Potsdam Institute for Climate Impact Research in Germany.
"Carbon dioxide emissions cannot be allowed to continue to rise if humanity intends to limit the risk of unacceptable climate change. The task is urgent and the turning point must come soon. If we are to avoid more than 2 degrees Celsius warming, which many countries have already accepted as a goal, then emissions need to peak before 2020 and then decline rapidly."
Professor Richard Somerville, Scripps Institution of Oceanography, University of California, San Diego, USA.
"We have already almost exceeded the safe level of emissions that would ensure a reasonably secure climate future. Within just a decade global emissions need to be declining rapidly. A binding treaty is needed urgently to ensure unilateral action among the high emitters."
Professor Matthew England, ARC Federation Fellow and joint Director of the Climate Change Research Centre of the University of NSW, Australia.
"This is a final scientific call for the climate negotiators from 192 countries who must embark on the climate protection train in Copenhagen. They need to know the stark truth about global warming and the unprecedented risks involved."
Professor Hans Joachim Schellnhuber, Director of the Potsdam Institute for Climate Impact Research (PIK) and Chair of the German Advisory Council on Global Change (WBGU).
"The adjustment of glaciers to present climate alone is expected to raise sea level by approximately 18 centimeters. Under warming conditions glaciers may contribute as much as more than half a meter by 2100.”
Dr. Georg Kaser, Glaciologist at the University of Innsbruck, Austria.
“Warming of the oceans and increased uptake of CO2 is of increasing concern for the marine environment. The loss of biodiversity due to upper ocean warming, ocean acidification and ocean de-oxygenation will add dramatically to the existing threads of overfishing and marine pollution".
Professor Martin Visbeck, Professor of Physical Oceanography and Deputy Director of IFM-GEOMAR.
"The climate system does not provide us with a silver bullet. There is no escape but to start reducing greenhouse gas emissions as soon as possible."
Professor Nicolas Gruber, Professor for Environmental Physics, ETH Zürich.
"Climate change is coming out even clearer and more rapidly in the recent data. The human contribution is not in doubt."
Professor Corinne Le Quéré, University of East Anglia School of Environmental Sciences, UK
"Climate change is accelerating towards the tipping points for polar ice sheets. That’s why we’re now projecting future sea level rise in metres rather than centimeters."
Professor Tim Lenton, University of East Anglia School of Environmental Sciences, UK
"Reducing tropical deforestation could prevent up to a fifth of human CO2 emissions, slowing climate change and helping to maintain some of the planet’s most important hotspots of biodiversity."
Professor Peter Cox, Climate System Dynamics at the University of Exeter, UK
"New ice-core records confirm the importance of greenhouse gasses for past temperatures on Earth, and show that CO2 levels are higher now than they have ever been during the last 800,000 years. The last time Earth experienced CO2 levels this high was millions of years ago."
Professor Jane Francis, University of Leeds, UK
"The reconstruction of past climate reveals that recent warming in the Arctic and in the Northern Hemisphere is highly inconsistent with natural climate variability over the last 2000 years."
Dr Alan Haywood, Reader in Paleoclimatology, the University of Leeds, UK
Climate change accelerating beyond expectations, urgent emissions reductions required, say leading scientists
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