Climate change could cause damages equivalent to up to 20% of GDP in the UK if global warming reaches 4°C by 2100, new study finds

Climate change could cause damages equivalent to 20 per cent of gross domestic product (GDP) in the UK by the end of the century if the rise in global temperature reaches 4 Celsius degrees, according to a new study published today in the journal ‘Nature Climate Change’.

An international team of researchers, led by Dr James Rising of the University of Delaware, applied the latest analysis of direct and indirect impacts of climate change to arrive at the most comprehensive assessment made to date for the UK.  

They found that current warming is causing damages equivalent to between 1 and 4 per cent of GDP, and that these would grow to between 2 and 20 per cent by 2100 if there is continued growth in annual global emissions of greenhouse gases and global mean surface temperature reaches 4 Celsius degrees above its pre-industrial level.

The authors of the paper on ‘Comprehensive national climate damage assessments framework applied to the UK’ found that half the expected total damages would be due to catastrophic impacts, such as destabilisation of the polar ice caps and rapid sea level rise, and other so-called “missing risks” that cannot currently be quantified with certainty.

Another major contribution to damages in the UK would be so-called “spillover effects” due to the impacts of climate change in other countries that disrupt trade, for instance.

Their central estimate for the total impacts of climate change on the UK is loss to both the economy and human welfare equivalent to a 10 per cent loss of GDP. However, the distribution of impacts across regions in the UK also matters, because poorer communities are more at risk. When the authors estimate a total welfare loss that accounts for this higher human cost, they find that the total risks are equivalent to a 15 per cent loss of GDP.

The authors warn that although this is the most comprehensive assessment yet of the potential impacts of climate change in the UK, it is still highly uncertain and may not include all possible damages.

The authors write: “Across the channels, the largest risk factor is catastrophic risk, reflecting the potential for global economic disruption, but spillover risks through trade, labour productivity losses and missing risks are also large”.

The authors point out that their study also omits a full range of adaptation options to the impacts of climate change. They write: “As a result, it is difficult to say whether we are more at risk of underestimating or overestimating total damages.”

The authors find that a scenario in which annual emissions are cut strongly to limit warming below 2 Celsius degrees by the end of the century would reduce damages to the equivalent of between 1 and 7 per cent of GDP.