The world’s current trajectory of greenhouse gas emissions poses significant threats to economic development as well as environmental sustainability. Projected increases in global temperatures and other changes, if not arrested, could pose serious challenges to maintaining critical ecosystems, coping with extreme events, and safeguarding health. An unprecedented cut in global emissions would be required to mitigate these risks, however, and accomplishing that would necessitate international agreement on implementation of some costly changes in energy and other sectors that has so far remained elusive.
In a recent Policy Research Talk, Michael Toman, research manager in the World Bank’s research department, discussed the challenge of controlling climate change, weaving together the latest scientific and economic evidence on the topic. The Policy Research Talks are a monthly event held by the research department to foster a dialogue between World Bank researchers and operational colleagues.
Toman described the task of mitigating global climate change as a ‘wicked problem’. “Climate change is an issue that presents great scientific and economic complexity, some very deep uncertainties, profound ethical issues, and even lack of agreement on what the problem is,” said Toman. “Economists will generally think about the trade-offs involved. Ecologists will talk about the idea that we’re driving towards the edge of a cliff. I think both views are right. The question is, how do you reconcile these two – if you can?”
According to the Fifth Assessment Report from the Intergovernmental Panel on Climate Change (IPCC), between 1970 and 2010 greenhouse gas emissions increased steadily, at an average rate of 1.3 percent per year. During that timeframe, regional patterns of emissions shifted significantly, with upper middle-income countries increasing their emissions threefold as their economies advanced. The IPCC review indicates that continuing on a trajectory without significantly increased efforts to reduce emissions growth would lead to an increase in global average temperature of between 3.7 and 4.8°C by the end of the century compared to pre-industrial conditions. While this change seems small, it is enough to cause major and disruptive environmental effects that will hurt economic development and human well-being.
Many scientists and policy advocates have called for deep cuts in emissions levels (not just growth rates) over the next few decades that would hold the likely increase in global temperature closer to 2°C. Moving from a 4°C to a 2°C trajectory would require unprecedented mitigation efforts: annual greenhouse gas emissions would need to be at least halved by 2050, even as many developing countries’ energy needs remain woefully underserved.