High chance that current atmospheric greenhouse concentrations commit to warmings greater than 1.5 °C over land

Press release 2016/03 - Issued by the Centre for Ecology & Hydrology, UK

High chance that current atmospheric greenhouse concentrations commit to warmings greater than 1.5 °C over land


Current levels of atmospheric greenhouse gas concentrations already commit the planet to air temperatures over many land regions being eventually warmed by greater than 1.5°C, according to new research published today (27 July 2016) in the journal Scientific Reports.

The results of the new study have implications for international discussions of what constitutes safe global temperature thresholds, such as 1.5°C or 2°C of warming since pre-industrial times. The expected extra warming over land will influence how we need to design some cities. It could also impact on the responses of trees and plants, and including crops. 

The research was carried out by scientists from the UK’s Centre for Ecology & Hydrology and the University of Exeter, UK.

The research team found two main reasons behind the result. 

First, even if it was possible to keep carbon dioxide concentrations fixed at their current 400 parts-per-million concentration levels, then the planet would continue to warm towards new equilibrium higher temperatures. At present, the climate is out of equilibrium, with the oceans drawing down very large amounts of heat from the atmosphere. However this will decline as the planet is bought towards a stable climatic state.  

Second, warming rates over land are far higher than those when averaged globally which include temperatures over the oceans. This is a feature observed in meteorological measurements and reproduced across a large suite of climate models.

Lead author Dr Chris Huntingford from the Centre for Ecology & Hydrology said, "It would certainly be inappropriate to create any additional fear over climate change. However, what this paper does is re-iterate that the oceans are currently acting as a very strong sink of heat. Even if carbon dioxide was somehow stabilised at current levels, additional warming will occur as we move towards an equilibrium climate state. Furthermore, both data and computer models all indicate enhanced temperatures over land, compared to global mean warming that includes temperatures over the oceans."

Co-author Dr Lina Mercado, Senior Lecturer in Physical Geography at the University of Exeter, said, “Our findings suggest that we are committed to land temperatures in excess of 1.5°C across many regions at present-day levels of greenhouses gases. It is therefore imperative to understand its consequences for our health, infrastructure and ecosystem services upon which we all rely.”

Dr Chris Huntingford added, “Central to our methodology is analysis of predictions made by a large number of independent climate research centres from around the world. Although many simulations exist for climate stabilisation, these tend to be at future higher greenhouse gas concentrations. We were able to scale these back to see the warming levels we are already committed to, even if present-day concentrations increased no further. Such computer models capture how the ocean heat sink would be slowly lost as a stable climate is approached, implying that temperatures would continue to increase temporarily even if greenhouse concentrations were fixed at current levels.”

This research was funded by the NERC National Capability fund.

Contact details

Centre for Ecology & Hydrology Press Office

Dr Chris Huntingford 
Dr Lina Mercado 

A copy of the full paper will be supplied on request.

Paper reference

Huntingford, C. and Mercado, L. M. High chance that current atmospheric greenhouse concentrations commit to warmings greater than 1.5 °C over land. Sci. Rep. 6, 30294; doi: 10.1038/srep30294 (2016).

On publication, the paper will be freely available online.

Additional information

The Centre for Ecology & Hydrology (CEH) is the UK's Centre of Excellence for integrated research in the land and freshwater ecosystems and their interaction with the atmosphere. CEH is part of the Natural Environment Research Council (NERC), employs more than 450 people at four major sites in England, Scotland and Wales, hosts over 150 PhD students, and has an overall budget of about £35m. CEH tackles complex environmental challenges to deliver practicable solutions so that future generations can benefit from a rich and healthy environment. www.ceh.ac.uk You can follow the latest developments in CEH research via twitter www.twitter.com/CEHScienceNews and our rss news feed http://www.ceh.ac.uk/rss/rss.xml

The University of Exeter is a Russell Group university that combines world-class research with very high levels of student satisfaction. Exeter has over 21,000 students and is one of the global top 100 universities according to the Times Higher Education World University Rankings 2015-16, positioned 93rd. Exeter is also ranked 7th in The Times and The Sunday Times Good University Guide 2016 and 11th in the Guardian University Guide 2017. In the 2014 Research Excellence Framework (REF), the University ranked 16th nationally, with 98% of its research rated as being of international quality. Exeter was named The Times and The Sunday Times Sports University of the Year 2015-16, in recognition of excellence in performance, education and research.  Exeter was The Sunday Times University of the Year 2012-13. 
The University will launch its flagship Living Systems Institute in 2016, a world-class, interdisciplinary research community that will revolutionise the diagnosis and treatment of diseases. This follows recent investments of more than £350 million worth of new facilities across its campuses in recent years; including landmark new student services centres - the Forum in Exeter and The Exchange on the Penryn Campus in Cornwall, together with world-class new facilities for Biosciences, the Business School and the Environment and Sustainability Institute. 
www.exeter.ac.uk

NERC is the UK's main agency for funding and managing world-class research, training and knowledge exchange in the environmental sciences. It coordinates some of the world's most exciting research projects, tackling major issues such as climate change, food security, environmental influences on human health, the genetic make-up of life on earth, and much more. NERC receives around £300m a year from the government's science budget, which it uses to fund research and training in universities and its own research centres. www.nerc.ac.uk

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