Leaked IPCC report: scientists 95% certain over man-made warming

Intro

Scientists are now more certain than ever that human activity is driving global warming, according to Reuters journalists who analysed a leaked scientific review from the United Nations. The leaked document is a draft of the upcoming Intergovernmental Panel on Climate Change’s (IPCC) report – which represent the most comprehensive global overview to date of the science behind climate change. The draft reveals that scientists from around the world agree it is 95% likely that human activities – such as burning fossil fuels – have been the main cause of climate change since the 1950’s. The report, which is still in draft form and due to be discussed by governments before its publication next month, will “add an exclamation mark on what we already knew” about the dangers of ongoing climate change, observed climate scientist Dr Michael Mann. The draft report also makes clear that based on current rates of fossil fuel emissions and temperature rise, the world is on track to overshoot the internationally agreed warming limit of 2ºC. Beyond 2ºC the impacts of climate change become globally devastating, according to recent research by the World Bank and others.

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MT @MartinScribbles New IPCC report ‘an exclamation mark on what we already knew’ – global warming caused by humans http://bit.ly/17Wp8II

Key Points

  • Scientists from around the world now agree it is at least 95 percent likely that human activities – such as burning fossil fuels – are the main cause of global warming since the 1950s, according to a leaked UN scientific assessment. Reuters obtained a draft of the Intergovernmental Panel on Climate Change’s (IPCC) first major report since 2007 which reveals greater certainty about the science behind climate change.
  • The ‘unequivocal’ evidence for global warming induced sea level rise, outlined in the forthcoming IPCC report, demonstrates why we should be talking about climate impacts. The world has only warmed 0.8ºC from pre-industrial levels but this has already been enough to trigger sea level rise. The IPCC warn that the oceans could rise nearly 1 meter by the end of this century, threatening hundreds of millions of people who live just a few metres or less above sea level.
  • The IPCC was set up to provide governments with the crucial information they need to assess the climate threat and take action, this leak suggests that time is running out for governments to prevent catastrophic levels of warming. The damages of climate change and the high carbon economy may already be costing $1.2 trillion every yearnow it appears that the IPPC’s comprehensive review of the science will tell us we are heading into deeper and darker territory where the costs will mount even higher.

Background

The leaked draft of the UN Intergovernmental Panel on Climate Change’s (IPCC) next major report – due out in September – shows that climate scientists from around the world are now clearer than ever before that climate change is being driven by human activities. According to the draft, the panel of experts say it is at least 95% likely that human activities are the main cause of warming since the 1950s. This is a jump from 90%  in the 2007 IPCC report, 66% in 2001, and just over 50% in 1995. If published in the final draft, this increase clearly shows that as the knowledge of climate science develops, so does the consensus that human activities – namely burning fossil fuels – are driving climate change; steadily squeezing out the arguments by a small minority that natural variations in the climate might be to blame. The latest research should further help shift the debate from the whether or not humans are causing global warming, to the extent of temperature rise and its likely impacts.

The IPCC report offers an overall assessment of the state of climate science to date. While there are many other climate reports that synthesise the science, the IPCC is the largest, and the latest round of reports – to be released in 2013 and 2014 – are expected to be the most comprehensive review of climate science undertaken yet. IPCC reports are one of the main guides used by governments to take the necessary action to prevent catastrophic global warming and adapt to the impacts of climate change. Governments have internationally agreed that global temperature rise must not surpass 2ºC above pre-industrial levels. This is seen as the threshold beyond which the most severe effects are felt, including more heatwaves, extinctions, floods and rising sea levels. This latest report comes as governments work towards a new international deal to rein in rising emissions, and limit global warming – set to be agreed in 2015. New research from Carbon Tracker and the World Bank warn that the current level of government action means the world is on track to warm by around 3ºC this century, the IPCC concur that it is unlikely we will limit warming to just 2ºC in this period. Using more complex computer models, and taking into account more factors, the leaked report shows that temperatures could rise anywhere between 1ºC to almost 5ºC. This is a wider range at both ends than the previous report in 2007.

While the certainty surrounding climate change has increased, it remains difficult to predict the impact in specific regions in coming decades, highlighting the need for more research in this area. While we know that many kinds of extreme weather events will get more intense, last longer and happen more frequently, where these events will occur is harder to predict. For example, while the new study is expected to state with greater confidence than in 2007 that rising greenhouse gas emissions have already meant more heatwaves, the science is less than certain about where in the world these heatwaves might occur, making regional planning much harder. If anything, scientists believe this uncertainty further validates the need to act “protectively and proactively” when it comes to limiting climate change, and is an example of how adaptation can be more difficult and more expensive than reducing greenhouse gas emissions.

While uncertainty remains in some of the IPCC’s findings, there are key areas where scientific understanding has developed over the last five years. The evidence for climate change induced sea level rise is now “unequivocal”, according to the reports of the leaked draft. The IPCC projects sea level will rise by between 29 and 82 cm (11.4 and 32.3 inches) by the late 21st century. This is an increase from the 18 to 59 cm in the last report, which did not fully account for changes in Antarctica and Greenland. This rise could have huge consequences for more than 1 billion people who live in low lying coastal regions. With hundreds of millions of people living a few metres or less above sea level, communities in rich and poor countries alike could be forced to endure the huge financial burden of improving coastal protect and, in some cases, complete relocation. Asian countries, particularly Vietnam, India and China are facing the greatest potential damages. But some communities are already being hit hard. Nearly all the population and therefore most of the national economy of the low-lying archipelagos of the Maldives and the Bahamas are now under threat. Island nations, including the Marshall Islands – where record tides this year have engulfed the countries islands - are calling for greater leadership to tackle the impacts they are already seeing on their way of life, and others, including Kiribati are already talking about re-location. In Fiji, communities have already had to relocate further inland as sea level rise and coastal erosion have already forced them from their homes. Australia is already being urged to prepare itself for an influx of climate refugees. Similar warnings have been made in the UK and the US. A new World Bank report warns that flood damage to the world’s largest cities by 2050 could reach $1 trillion, unless they improve defences, as cities become more prone to climate related flooding.

While there are still, unsurprisingly, uncertainties surrounding the impacts of climate change, governments cannot afford to wait for every detail to be laid out with 100% certainty as the risks are far too high. The latest draft of the IPCC report shows that scientists are more certain than ever about how humans are changing the climate, and it is clear that we now know enough to take action to stop the worst impacts from occurring. When it is published this IPCC report will follow a host of others, released over the last year, that highlight the need for urgent action. A recent report from the International Energy Agency called for urgent government action to clean up the global power sector and stave off catastrophic climate change, while the World Bank warned that the window for holding warming below 2ºC is closing rapidly, painting a stark picture of a world where climate change continues unabated. Both the World Meteorological Organisation (WMO) and the National Oceanic and Atmospheric Administration (NOAA) have also highlighted the increase in global warming, the WMO examining record breaking temperatures over the last decade and the NOAA the year of record breaking extreme weather events in 2012.

The final version of the report is to be released at the end September. The leaked report is the latest draft of the IPCC report, and it will continue to undergo a writing and review process ahead of the four-day approval session in Stockholm on 23-26 September, where the final draft of the report will be released.

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Key quotes

The report is simply an exclamation mark on what we already knew: Climate change is real and it continues unabated, the primary cause is fossil fuel burning, and if we don’t do something to reduce carbon emissions we can expect far more dangerous and potentially irreversible impacts on us and our environment in the decades to come - Dr Michael Mann, Climate Scientist

“We can confidently say that the risk of drought and heat waves has gone up and the odds of a hot spot somewhere on the planet have increased but the hotspot moves around and the location is not very predictable. This year perhaps it is East Asia: China, or earlier Siberia? We can name spots for all summers going back quite a few years: Australia in 2009, the Russian heat wave in 2010, Texas in 2011, etc. Similarly with risk of high rains and floods: They are occurring but the location moves.” - Dr Kevin Trenberth, Climate Scientist 

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More tweets

MT @GaryM “With the forthcoming IPCC report, the contrarians finally agree we are changing the #climate” http://t.co/XhiTjUWPiN

MT @CICERO_klima Scientists surer than ever that human activity is causing global warming, acc. to draft #IPCC report http://bit.ly/16TYDGW

MT @MichaelEMann “Climatologists more certain global warming caused by humans” http://bit.ly/17Wp8II via @ClimateProgress #IPCC

MT @carlosrittl Leaked IPCC drafts lift confidence in humans’ carbon culpability http://bit.ly/1dlcglr

@HarishUniyal IPCC report confirms carbon pollution is caused by humans & impacts speeding up http://thkpr.gs/17Wp8IH via @climateprogress

@rtcc_edking Forthcoming IPCC report likely to increase sea level rise predictions to 29-82 cm before 2100 http://bit.ly/14aqQsG

MT @GiaSilvestrini #IPCC report: 95% likely that human activities main cause of #warming since 1950s. 66% in 2001 http://bit.ly/1eWMFNE

MT @fainest “Time and time again, the world’s best scientists have sent us clear messages.” http://bit.ly/15YqS2v via @guardian #IPCC