Assessing the costs of adaptation to climate change

The International Institute for Environment and Development (UK) and the Grantham Institute for Climate Change, Imperial College London (UK) have released a report to assess the costs of adaptation to climate change compared with estimates from different studies, particularly UNFCCC estimates.

The timing couldn't be better: UNFCCC is preparing a pos-Kyoto agreement in December, in Copenhagen and Ban Ki-Moon has stated that tackling climate change should be a worldwide commitment.

How expensive it is to adapt to climate change? Is it cheaper to start mitigating climate change now when consequences are not yet fully known and felt? What are the cost uncertanties?

Several studies have estimated the cost of adaptation to climate change (Figure 1. and Figure 2.)
Figure 1. Costs in developing countries, for 2010-2015
Figure 2. UNFCCC estimates of addtional annual investment needed by 2030

This study concludes that UNFCCC may be underestimating, because of assumptions. For example for Human Health...

"Human health
The UNFCCC estimates of costs of adaptation are the costs of the intervention set to prevent the additional burden of disease due to climate change for three health outcomes in low- and middleincome countries: diarrhoeal diseases, malaria and malnutrition. The estimates are in the range of $4–12 billion per year in 2030.
These three outcomes are not the total projected burden on human health from climate change.
That total has yet to be assessed accurately, but authors of the WHO study of the global disease burden estimate that these outcomes amount to 30–50% of the probable future total burden in 2030 in low- and middle-income countries (McMichael and Bertollini, 2009, personal communication).
A potential source of under-estimation is that the UNFCCC considers a narrow range of
development futures. It takes a single median population projection in which population numbers increase and cases of diarrhoea/malaria/malnutrition remain constant, i.e. there is steep relative decline in incidence. The present study considers this to be an optimistic assumption."