October 24, 2011
Global Temps Projected To Increase By 2 Degrees
Two research papers, each appearing in the journal Nature Climate Change, have warned that if greenhouse gas emissions continue to increase, global temperatures could exceed “safe” levels of two degrees Celsius in some regions of the world by 2060.
Even if the 2C threshold is inevitable, reducing emissions now could delay that rise by up to several decades, giving us much needed time to adapt to climate change.These are the conclusions of new research by scientists from the National Center for Atmospheric Science (NCAS) based at the University of Reading's Walker Institute, the UK Met Office and from the University of Oxford.
“Certain levels of climate change are very likely within the lifetimes of many people living now ... unless emissions of greenhouse gases are substantially reduced in the coming decades,” according to the researchers.
“Large parts of Eurasia, North Africa and Canada could potentially experience individual five-year average temperatures that exceed the 2 degree Celsius threshold by 2030 -- a timescale that is not so distant,” said the study.
Industrialized nations in 2009 set a 2 degree Celsius warming as the maximum limit to avoid dangerous floods, droughts, rising oceans, and other climatic disasters. Although some experts said a 1.5 degree limit would be much safer.
Yet, the general consensus among scientists is that global pledges to curb greenhouse gas emissions are not strong enough to prevent “dangerous” climate change. Nations will meet next month at the UN Climate Summit in Durban, South Africa, where a binding pact to reduce emissions looks unlikely to be signed. Instead, it is likely to be 2014 or 2015 before such a deal can be struck.
Dr. Manoj Joshi, lead author of the research, says experts should be addressing the question “when are serious impacts expected?,” rather than “what serious impacts are expected?”
“It is not just about avoiding potentially dangerous climate change, but also about buying time for adaptation,” he told Reuters in an interview.
Joshi´s research found that most of the world´s land surface is likely to experience five-year average temperatures that exceed 2C above pre-industrial levels by 2060. That threshold could be extended far longer if emissions are curbed now.
But even if global temperature rises are kept under the 2C threshold, some regions of the world will still not be able to avoid warming and the likelihood of severe climate disasters, such as extreme heat waves.
Additionally, thresholds will be exceeded in individual years before being exceeded consistently year on year, because of natural variability in climate. Such variability has profound implications for planners who must decide if a single year or two above the threshold can be tolerated, and at which point adaptable measures need to be implemented.
“This approach to communicating the impacts and uncertainties of climate change draws attention to rates of change rather than just the change itself. It complements existing methods, and should be employed more widely,” said Joshi.
In a separate study by academics from Zurich´s Institute for Atmospheric and Climate Science, the Potsdam Institute for Climate Impact Research and the UK's Met Office Hadley Center, scientists said it would be challenging to limit temperature rises to two degrees Celsius.
To achieve a greater than 66 percent chance of limiting temperature rise, global emissions will most likely need to peak before 2020 and fall to about 48 gigatons per year by 2100.
“Without a firm commitment to put in place the mechanisms to enable an early global emissions peak followed by steep reductions thereafter, there are significant risks that the 2 degree target, endorsed by so many nations, is already slipping out of reach,” said that study.
Over the course of the 20th century, global temperatures have risen to around .75 degrees Celsius over pre-industrial levels. According to data from the Hadley Center, the warmest year on record (1998) was about 0.9C above pre-industrial levels, due to global warming, and also the El Nino climate phenomenon.
On the Net:
- Nature Climate Change
- National Center for Atmospheric Science
- University of Reading Walker Institute
- UK Met Office
- University of Oxford
- UN Climate Summit - Durban (COP17)
- Institute for Atmospheric and Climate Science - Zurich
- Potsdam Institute for Climate Impact Research
- Hadley Center