Poorest countries suffer most from global warming

Martin Wolf: The linked challenges of climate and development will shape humanity’s future

“Right, as the world goes, is only in question between equals in power, while the strong do what they can and the weak suffer what they must.”

This sentence from the History of the Peloponnesian War by Thucydides is the philosophy of Donald Trump's administration. Thus, two of his advisers, HR McMaster and Gary Cohn, wrote in May that: "The world is not a 'global community' but an arena where nations, non-governmental actors and businesses engage and compete for advantage."

This amoral perspective has serious implications. In no area are global spillovers more significant and co-operation more vital than climate. The failure to act ensures that the poor would indeed suffer.

This is the conclusion of a chapter on the economic impact of weather shocks, in the International Monetary Fund’s latest World Economic Outlook. The largest negative impacts of the shocks being made more frequent by global warming are on tropical countries.


Nearly all low-income countries are tropical. Yet these countries are the least able to protect themselves. Thus they are innocent victims of changes for which they bear no responsibility.


In assessing these risks, one has to start from the proposition that anthropogenic global warming is a reality. The intellectual industry devoted to denying this is well-funded and noisy. But its arguments are highly unconvincing. The underlying physics are undeniable.

Furthermore, the empirical connection between rising concentrations of greenhouse gases and temperature is unambiguous. If little or no action is taken, average temperatures could rise by 4°C, or more, above pre-industrial levels by the end of the century. Aware of the lengthy lead times needed if effective action is to be taken, both to mitigate climate change and adapt to it (where inescapable), rational people would act now.

The main obstacles to such action are three. First, specific economic interests, notably in the fossil fuel industry, are understandably opposed to action and, not infrequently, to the science that suggests it is necessary.

Second, free-marketeers, who despise both governments and environmentalists, reject the science, because of its (to them) detestable policy implications. Third, few wish to inconvenience themselves, let alone threaten their standard of living, for the sake of the future, or people in poorer countries.

So what is the evidence of the impact on the poorest of failure to act? The IMF authors start from our knowledge that higher temperatures make a range of weather-related disasters more likely because there will be more energy in the weather system.

Such effects will include a greater frequency of - and greater damage done by - cyclones, floods, heatwaves and wildfires.

Furthermore, the increased frequency of extreme events will also do relatively more damage to the poorest countries. This is so for two reasons: these countries are located in the regions of the world most likely to be adversely affected; and they are least able to protect themselves against, or manage, the impact.

For the median low-income developing country, with an average temperature of 25°C, the effect of a 1°C increase in temperature is to lower that year’s growth by 1.2 percentage points.


Moreover, the impact is long-lasting. These costs come from the adverse effects of heat on productivity, agricultural output, health and even conflict. Extreme heat is costly. Adaptation to extreme weather remains very hard for poor countries. We have witnessed this autumn the far more damaging impact of huge storms on poorer countries, such as those in the Caribbean, than on the much wealthier US.

It is possible for well-managed nations to reduce these adverse impacts. Countries with superior infrastructure, better-regulated capital markets, flexible exchange rates and more accountable and democratic institutions recover faster economically from the adverse impact of temperature shocks than others.

Hot regions in high-income countries also cope better than those in poorer ones. All this supports the view that the poorest countries are likely to be the most damaged by rising temperatures. The populations of such countries are more vulnerable because they are closer to subsistence.

With the temperature increases projected by 2100 under unmitigated climate change, annual real incomes per head of a representative low-income country would be 9 per cent lower than they would otherwise be.

This would impose large costs on their vulnerable groups. Moreover, such a forecast ignores the risks and uncertainties around any such estimates. A planet 4°C warmer than the pre-industrial average would be so different from the one we are now used to that the implications are in significant part unknowable.


The IMF’s analysis has a number of serious implications.

First and most important, low-income countries need to develop quickly to be better able to cope with weather shocks.

Second, their development needs to be consistent with mitigating the rise in global temperatures.

Third, we need rapid improvements in the relevant technologies and their swift dissemination.

Fourth, we also need to help poor countries adapt to the changes in climate already sure to happen.

Fifth, we need to develop insurance against weather-related shocks to poor countries. Finally, a moral case also exists for compensating losers from the costs of the unmitigated climate changes being imposed by richer countries.

We should not let the urgent stop us from thinking about the important. The linked challenges of climate and development will shape humanity’s future.

Copyright The Financial Times Limited 2017