Global ChangeIntersection of Nature and Culture

Extreme climate and the vulnerability of least-developed countries

Wednesday, January 6th, 2010

Happy New Year, everyone.  Sorry for the lag in posts, but there wasn’t a lot happening in the news or journals over the past week.

A few years ago, I saw a talk by Thomas Schelling (Nobel laureate in economics) who argued that we need to accelerate the economic development of poor countries so that they are able to cope with climate change.  This analysis is interesting, if not fraught with additional challenges, such as development in a carbon-based energy world hastening the very problem to which these nations are attempting to adapt.

In an article¹ in the Early Edition of the Proceedings of the National Academy of Sciences (open access), Anthony Patt and colleagues argued that the need for assistance by Least Developed Countries (LDCs) is dependent on vulnerability, which, in turn, depends on both exposure to climate change and how socioeconomic factors affect the sensitivity of LDCs to climate change.

To assess this hypothesis, they first examined how deaths caused by disasters (floods, droughts, and storms) varied across the level of development in several LDCs.  They used the UN Human Development Index—HDI, a composite metric of income, education, and life expectancy—as a proxy for development.

Here’s what they found…

As you might expect, they found that deaths declined with increased HDI, but interestingly, the relationship had a peak in the middle, suggesting that as the least-developed countries become more developed, they may actually exacerbate vulnerability to climate change at mid levels of HDI before eventually reducing vulnerability at high levels of HDI.

Next, they focused on Mozambique as a case study.  Using the model of deaths vs. HDI they developed for other countries, they projected how Mozambique’s HDI might change over the next 50 years.  To do this, they linked the HDI to different development scenarios outlined by the IPCC’s Special Report on Emissions Scenarios (SRES):

The A2 storyline describes high population and economic growth but low globalization, whereas the B1 storyline describes greater globalization
tied to improvements in environmental quality and sustainability, as well as lower population growth.

Under both scenarios, carbon increases in the atmosphere, but at different rates and to different degrees.  The authors assumed a linear increase in storms/disasters with rising temperatures, indicating that greater warming in the A2 scenario will lead to more disasters and more potential death than the B1 scenario where warming is not as great.

Following the B1 scenario caused the HDI to rise more quickly than the A1 scenario.  Simply put, society on a more-sustainable path (B1) leads to higher social welfare than under a more fossil-fuel intensive path with higher levels of human population (A2).

Similar to what they found by examining many countries, Mozambique will become more vulnerable to increased deaths as HDI rises over coming decades (by 2030-2040).  However, after 2050, vulnerability declined significantly in the B1 scenario, less so in the A2 scenario.

A few excerpts of their conclusions:

The results suggest that vulnerability may rise faster in the next two decades than in the three decades thereafter. Importantly, the overall need for adaptation measures will continue to rise… However,
assuming that their development paths fall somewhere close to the range bounded by the A2 and B1 scenarios, by the second quarter of the century LDCs will likely engage in a greater share of this adaptation autonomously, thereby reducing both their losses, and their need for financial assistance. This is especially the case if socio-economic conditions change in a manner close to that described in the B1 scenario.

….Looking beyond 2060 and the crossing of temperature thresholds such as 2 °C, it may well be that steadily rising climate impacts—such as sea level rise or the effects of cumulative changes on ecosystems—create problems that go well beyond the ability of any country, rich or poor, to adapt. Until that point, a primary argument for ramping up assistance slowly—namely, that adaptation needs can only increase as climate change continues—is incomplete, because it ignores the role that socio-economic development and the concurrent changes in adaptive capacity will have to play. Although there are important caveats to our results, they provide a first estimate of how vulnerability will unfold over the next 50 years, if one assumes, as do all of the SRES scenarios, that
incomes will continue to rise. They suggest that the urgency of efforts to reduce vulnerability, including the provision of international financial assistance, is high.

One thing the authors acknowledge is that nobody really has a good explanation for the humped relationship of HDI vs. deaths from disasters.  That’s an important part of their results, which suggests that the very poorest nations may experience more suffering in the initial steps of development.  Understanding this would make a great PhD in development economics.

¹Patt, A. et al. (in press) Estimating least-developed countries’ vulnerability to climate-related extreme events over the next 50 years. Proceedings of the National Academy of Sciences.

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