Experts have warned that a decade of insufficient political action on climate change has left the world with a vast gap between the current trajectory of global emissions, and where they should be heading in order to meet the goals set out in the Paris Climate Agreement.  

Scientists from over ten countries, including Professor Joseph Alcamo, Director of the University’s Sussex Sustainability Research Programme, have revealed that because the pace of efforts to reduce greenhouse gas emissions has been too slow over the past decade, this gap is four times larger than earlier estimations.  

The conclusions were published in a Comment piece in this week’s prestigious Nature journal, after a review of all ten editions of the Emissions Gap Report, which is produced yearly by the United Nations Environment Programme (UNEP).  These reports examine the difference (or ‘gap’) between what countries have pledged to do individually to reduce greenhouse-gas emissions, and what they need to do collectively to meet agreed temperature goals.  

The international team reported that, because carbon dioxide and other gases have been rapidly accumulating in the atmosphere, emissions need to be cut at an even faster clip than originally estimated – from 1.7% to nearly 3% per year in order to limit global warming to 2°c.  But to stay within the recommended 1.5 °c means emissions cuts of a 7% per year – rising drastically from the previously estimated 3.3%.  

A recent report by the Intergovernmental Panel on Climate Change warned that global warming of more than 1.5°c would cause clearly higher climate risks including increased frequencies of heat waves, heavy precipitation and droughts in various world regions.  

In the piece, the authors write ‘The gap is so huge that governments, the private sector and communities need to switch into crisis mode, make their climate pledges more ambitious and focus on early and aggressive action.’ 

Joseph Alcamo, Professor of Environmental Systems Science at the University of Sussex, initiated the Emission Gap Reports in 2010 and supervised the first five of these reports while Chief Scientist of UNEP. He said: “With the UK government hosting this year’s international Conference of Parties in Glasgow, it’s now the Government’s job to prod countries to cut emissions fast enough to avoid agreed-upon temperature limits going through the roof.”  

The Comment published this week also takes on a hopeful tone by acknowledging that climate actions are ramping up around the world – if not at the pace needed. 

Some countries, regions, cities and businesses have promised or implemented urgently needed climate action. For example, 76 countries or regions and 14 subnational regions or states have set or even begun implementing net-zero emissions goals. The authors say that closing the gap will require scaling up these few success stories and mirroring them with progress in every sector.   

Dr Niklas Höhne, lead author of the Nature comment and partner at NewClimate Institute in Germany, said: “Even if the gap has widened significantly in the last 10 years, it is encouraging to see how a fast growing number of countries, regions, cities and businesses show that the transition away from fossil fuels is possible. Now the rest of the world needs to follow their lead.” 

The piece also notes the link between achieving the UN Sustainable Development Goals (SDGs) and the climate goals, noting that actions to reduce greenhouse gas emissions are ‘essential for achieving food security, healthy lives, and many other SDGs’.  

Professor Alcamo said: “A key to rapid emission reductions will be to couple climate goals with other global goals, such as providing clean energy, securing our food supply, and ending inequality, as laid out in the Sustainable Development Goals. Protecting our climate cannot be a piecemeal exercise.”