Public Release:  CO2 warming effects felt just a decade after being emitted

Institute of Physics

It takes just 10 years for a single emission of carbon dioxide (CO2) to have its maximum warming effects on the Earth.

This is according to researchers at the Carnegie Institute for Science who have dispelled a common misconception that the main warming effects from a CO2 emission will not be felt for several decades.

The results, which have been published today, 3 December, in IOP Publishing's journal Environmental Research Letters, also confirm that warming can persist for more than a century and suggest that the benefits from emission reductions will be felt by those who have worked to curb the emissions and not just future generations.

Some of these benefits would be the avoidance of extreme weather events, such as droughts, heatwaves and flooding, which are expected to increase concurrently with the change in temperature.

However, some of the bigger climate impacts from warming, such as sea-level rise, melting ice sheets and long-lasting damage to ecosystems, will have a much bigger time lag and may not occur for hundreds or thousands of years later, according to the researchers.

Lead author of the study Dr Katharine Ricke said: "Amazingly, despite many decades of climate science, there has never been a study focused on how long it takes to feel the warming from a particular emission of carbon dioxide, taking carbon-climate uncertainties into consideration.

"A lot of climate scientists may have an intuition about how long it takes to feel the warming from a particular emission of CO2, but that intuition might be a little bit out of sync with our best estimates from today's climate and carbon cycle models."

To calculate this timeframe, Dr Ricke, alongside Professor Ken Caldeira, combined results from two climate modelling projects.

The researchers combined information about the Earth's carbon cycle--specifically how quickly the ocean and biosphere took up a large pulse of CO2 into the atmosphere--with information about the Earth's climate system taken from a group of climate models used in the latest IPCC assessment.

The results showed that the median time between a single CO2 emission and maximum warming was 10.1 years, and reaffirmed that most of the warming persists for more than a century.

The reason for this time lag is because the upper layers of the oceans take longer to heat up than the atmosphere. As the oceans take up more and more heat which causes the overall climate to warm up, the warming effects of CO2 emissions actually begin to diminish as CO2 is eventually removed from the atmosphere. It takes around 10 years for these two competing factors to cancel each other out and for warming to be at a maximum.

"Our results show that people alive today are very likely to benefit from emissions avoided today and that these will not accrue solely to impact future generations," Dr Ricke continued.

"Our findings should dislodge previous misconceptions about this timeframe that have played a key part in the failure to reach policy consensus."

From Tuesday 3 December, this paper can be downloaded from http://iopscience.iop.org/1748-9326/9/12/124002/article

###

Notes to Editors

Contact

1. For further information, a full draft of the journal paper or contact with one of the researchers, contact IOP Press Officer, Michael Bishop: Tel: 0117 930 1032 E-mail: michael.bishop@iop.org For more information on how to use the embargoed material above, please refer to our embargo policy.

IOP Publishing Journalist Area

2. The IOP Publishing Journalist Area gives journalists access to embargoed press releases, advanced copies of papers, supplementary images and videos. In addition to this, a weekly news digest is uploaded into the Journalist Area every Friday, highlighting a selection of newsworthy papers set to be published in the following week. Login details also give free access to IOPscience, IOP Publishing's journal platform. To apply for a free subscription to this service, please email Michael Bishop, IOP Press Officer, michael.bishop@iop.org, with your name, organisation, address and a preferred username.

Maximum warming occurs about one decade after a carbon dioxide emission

3. The published version of the paper 'Maximum warming occurs about one decade after a carbon dioxide emission' (2014 Environ. Res. Lett. 9 124002) will be freely available online from Wednesday 3 December. It will be available at http://iopscience.iop.org/1748-9326/9/11/114023/article.

Environmental Research Letters

4. ERL covers all environmental science, providing a coherent and integrated approach including research articles, perspectives and reviews. The journal's coverage reflects the increasingly interdisciplinary nature of environmental science and recognizes the wide range of contributions to the development of methods, tools and evaluation strategies relevant to the field.

IOP Publishing

5. IOP Publishing provides publications through which leading-edge scientific research is distributed worldwide.

Beyond our traditional journals programme, we make high-value scientific information easily accessible through an ever-evolving portfolio of books, community websites, magazines, conference proceedings and a multitude of electronic services.

IOP Publishing is central to the Institute of Physics, a not-for-profit society. Any financial surplus earned by IOP Publishing goes to support science through the activities of the Institute.

Go to ioppublishing.org.

Access to Research

6. Access to Research is an initiative through which the UK public can gain free, walk-in access to a wide range of academic articles and research at their local library. This article is freely available through this initiative. For more information, go to http://www.accesstoresearch.org.uk

The Institute of Physics

6. The Institute of Physics is a leading scientific society. We are a charitable organisation with a worldwide membership of more than 50,000, working together to advance physics education, research and application.

We engage with policymakers and the general public to develop awareness and understanding of the value of physics and, through IOP Publishing, we are world leaders in professional scientific communications.

In September 2013, we launched our first fundraising campaign. Our campaign, Opportunity Physics, offers you the chance to support the work that we do.

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.