Early emissions peak more relevant than emissions reduction rate: study

01/14/2012 - Avoiding negative impacts of global warming depends more on starting early to let greenhouse-gas emissions decline than on the rate of reductions after the peak. This is one key outcome of the first global-scale assessment of climate change impacts across sectors, from coastal flooding to crop failure, now published in Nature Climate Change. The analysis suggests that a policy of remaining below a 2 degrees Celsius temperature rise target could reduce impacts by 20 to 65 percent relative to a business-as-usual scenario.
Early emissions peak more relevant than emissions reduction rate: study

“There is considerable variability in the impacts avoided between the sectors”, the international team of authors points out, led by Nigel Arnell of the University of Reading and including two scientists affiliated with the Potsdam Institute for Climate Impact Research. “An emissions pathway peaking in 2016 and declining at 5 percent per year, for example, avoids between 58 and 66 percent of the adverse impacts of climate change on coastal flood risk, when assuming no upgrades in coastal protection measures – but only 30‐40 percent of the adverse impacts on crop suitability,” says Jochen Hinkel, guest scientist at PIK and senior researcher at the Global Climate Forum.

The authors put a strong focus on the remaining uncertainties. “The proportion of impacts avoided at the global scale is relatively robust for most indicators across different climate model patterns, but the absolute magnitude of avoided impacts varies considerably,” the study says. Also, only one impact computer simulation – a so-called model – is used in each sector. Furthermore, the indirect consequences of changes in one sector for another are not calculated.

The Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP), a community-driven effort coordinated by PIK, aims at advancing this strand of research. Based on common background scenarios (climate and socio-economic), a quantitative estimate of impacts and uncertainties for different sectors and from multiple impact models will be derived. Fast-track outcomes will be presented and discussed at the first Impacts World Conference in Potsdam this May and get published in special issues of the Proceedings of the National Academy of Sciences and of Earth System Dynamics.

 

Article: Arnell, N.W., Lowe, J.A., Brown, S., Gosling, S.N., Gottschalk, P., Hinkel, J., Lloyd-Hughes, B., Nicholls, R.J., Osborn, T.J., Osborne, T.M., Rose, G.A., Smith, P., Warren, R.F. (2013): A global assessment of the effects of climate policy on the impacts of climate change. Nature Climate Change (online)

 

Weblink to the article: http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate1793.html

Weblink to more information on the study: http://www.reading.ac.uk/news-and-events/releases/PR482917.aspx

Weblink to ISI-MIP and Impacts World Conference 2013: https://www.isimip.org