News | Monday, 30th September 2013

University at the heart of climate change debate

Professor lead author on prominent UN report

AN ENVIRONMENT expert from Manchester Metropolitan University (MMU) is at the heart of the United Nations’ new climate report which shows greenhouse gases are causing climate change.

Professor David Lee was a lead author on one of the chapters of the much-publicised Intergovernmental Panel on Climate Change (IPCC) fifth assessment report, known as AR5.

After four years of effort, the report, Summary for Policymakers, was released in Stockholm last week sending shockwaves around the globe. It predicts with ’95 per cent certainty’ that humans are the ‘dominant cause’ of climate change.

It caught the attention of industrial, political and cultural leaders around the world - saying there is little doubt that humans are to blame for climate change.

Lead author

Prof Lee, of MMU’s Centre for Aviation, Transport and the Environment, was lead author of 15 international experts for Chapter 8 - ‘Anthropogenic and Natural Radiative Forcing’.

His team already advises the UK’s Department for Transport, UN organisations and the European Commission.

The report involved a total of 209 lead authors and 50 review editors from 39 countries, creating 3,000 pages. The first part was released last week investigating the physical science of climate change, while the final two parts will be released over the coming year.

Professor Lee said: “This report represents a major milestone in our increased and better understanding of the science of the causes of climate change. The report highlights how the warming is ‘unequivocal’, and observations show how the atmosphere and oceans have warmed, snow and ice extent have decreased, and sea level has risen.

Watershed moment

“Of course the big question is: have the observed increased concentrations of greenhouse gases, including CO2, caused the observed changes? We have shown that global mean surface temperatures have increased by 0.85 degrees C over the period 1880 – 2012, which is more than the last assessment report in 2007.

“Our increased scientific understanding of the causes has led us to conclude that the human influence on the climate system is clear, and that it is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th Century.

“2013 represented a watershed in terms of CO2 concentrations in the atmosphere, when they reached 400 parts per million, unprecedented levels for 800,000 years. The sobering part of the science of CO2 is that for every tonne we emit, 30% will be removed from the atmosphere in a few decades, 50% in a few centuries, and the remaining 20% over millennia. So what we emit today, has massive long-term impacts for the future.

“The climate simulations in the IPCC report show that there is substantial ‘committed warming’ already, and if emissions are not reduced over the next 20 years, temperatures may increase beyond the value of 2 degrees C increase by 2100.”


The IPCC website and the Summary for Policymakers can be found at:

The work of Professor Lee and colleagues within the Centre for Aviation, Transport and the Environment, can be found at:

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