The University of Nottingham

Tough limits on global emissions of greenhouse gases could avoid 20 to 65% of the damaging effects of climate change by 2100 according to new research involving experts from The University of Nottingham and led by the University of Reading’s Walker Institute.

Dr Simon Gosling, an expert in climate change impacts in the School of Geography, assessed the effects of climate change on water stress. He said: “This is the first comprehensive assessment to show the benefits that global action on climate change could have across different sectors of society. Essentially, we found that the sooner emissions peak and decline, the greater the benefits are. Clearly, some sectors appear to benefit more than others, with crop productivity seeing greater benefits than water stress, for instance.”

The research is published in Nature Climate Change.

The most stringent emissions scenario in the study keeps global temperature rise below 2 degrees C and has global greenhouse gas emissions which peak in 2016 and then reduce at 5% per year to 2050. The 2 degree target is the focus of international climate negotiations, the latest round of which took place in Doha in December 2012. However, relatively little research has been done to quantify the worldwide benefits, in terms of avoided or reduced impacts, of the 2 degree target.

Of the impacts studied, crop productivity, flooding and energy for cooling are the areas that see the greatest benefit from emission reductions: global impacts in these areas are reduced by 40 to 65% by 2100 if warming can be limited to 2 degrees. In contrast, the adverse impacts of climate change on water availability are only reduced by around 20% when emission limitations are imposed. This is because even a small amount of warming can alter rainfall patterns sufficiently to reduce water availability.

Limiting emissions also has the effect of delaying climate change impacts by many decades. One example from the new research shows global productivity of spring wheat could drop by 20% by the 2050s, but such a drop in yields is delayed until 2100 with stringent emission limits. Similar delays are seen in increased exposure to flood risk and rising energy demand for cooling.

Professor Nigel Arnell, Walker Institute Director said: “Our research clearly identifies the benefits of reducing greenhouse gas emissions – less severe impacts on flooding and crops are two areas of particular benefit. Reducing greenhouse gas emissions won’t avoid the impacts of climate change altogether of course, but our research shows it will buy time to make things like buildings, transport systems and agriculture more resilient to climate change.”

Secretary of State for Energy and Climate Change, Edward Davey, said: “We can avoid many of the worst impacts of climate change if we work hard together to keep global emissions down. This research helps us quantify the benefits of limiting temperature rise to 2°C and underlines why it’s vital we stick with the UN climate change negotiations and secure a global legally binding deal by 2015.”

The new research provides the first comprehensive assessment of the benefits of limiting global greenhouse gas emissions. A range of impact indicators are considered including: flooding, water availability, crop productivity and energy for heating and cooling.

This research is part of the AVOID research programme funded by DECC/Defra and led by the Met Office in a consortium with the Walker Institute, Tyndall Centre and Grantham Institute. The research was led by the University of Reading’s Walker Institute in collaboration with the Met Office, University of Southampton, Tyndall Centre for Climate Change Research, The University of Nottingham, PIK in Potsdam (Germany), the University of Aberdeen and the University of East Anglia.

Reference: N W Arnell et al (2013).  A global assessment of the effects of climate policy on the impacts of climate change. Nature Climate Change, DOI: 10.1038/NCLIMATE1793