Richard Tol, the IPCC coordinating lead author on the economics of climate change, has participated in many studies on policies to combat climate change. A new study concludes that global warming would be significantly less costly if stringent mitigation measures are taken immediately.

The analysis by Prof Tol and colleagues shows that two-thirds of expected damages from present-day global warming could be avoided if temperatures are kept below 2 °C relative to preindustrial levels. The optimal level of mitigation is more costly for wealthier people, who will suffer relatively less than the poor from climate change.

The researchers used data on climate change impacts and economic damages that were previously calculated by other researchers in their models. They also used their own data on the costs of mitigation, in order to compare top-down and bottom-up approaches.

A new study published 19 June in Nature Climate Change shows that stringent climate change mitigation would be much less expensive than is generally accepted in impact studies. According to the authors, the optimal level of global warming given in this paper is less than the 2 °C often considered as a threshold above which climate change would become unmanageable. The optimal level of mitigation they find is more costly for wealthier people, who will suffer relatively less than the poor from climate change.

The results show that two-thirds of expected damages from present-day global warming could be avoided if temperatures are held below 2 °C relatives to pre-industrial levels, instead of the typically assumed threshold of 4 °C.
The study, conducted by researchers at the UEA’s Tyndall Centre for Climate Change Research, uses their modeling framework to compare mitigation costs of the top-down and bottom-up approaches. The authors used data on climate change impacts and economic damages that were previously calculated by other researchers in their models, but also their own data on the costs of mitigation.

According to co-author Professor Richard Tol from the UEA’s School of International Development, reducing emissions much below current levels would be costly for high emitters such as the United States, while reducing emissions much beyond present levels would be costlier still for high emitters.

“The larger mitigation effort is, the less onerous it becomes to avoid climate change damage,” he said. “This is also true for rich people who will need to spend relatively more than poor people to avoid most of the damages associated with 2 °C of warming.”

According to the paper, poor countries will benefit more than rich countries from mitigating global warming because they are likely to suffer relatively higher damages per tonne of carbon dioxide. The study also finds that mitigation is less costly in terms of economic growth when it is delayed until richer countries have reached their maximum economic capacity.

The paper concludes that global warming would be significantly less costly if stringent mitigation measures were taken immediately and not delayed until the economy reaches its maximum capacity, as has been assumed in previous studies. It also suggests that poorer people would benefit more from early action than richer people.
“The idea that we should wait and worry about the costs of climate change only when they threaten to derail economic growth deserves a lot more attention,” concluded co-author Dr. Chris Hope from the University of Cambridge. “This research should help policymakers and politicians to focus on actions that deliver the biggest benefits at the lowest cost.”