- No matter what we do, we are unlikely to avoid all of the impacts of climate change. Adaptation is unavoidable.
- At present the worldwide burden of human ill-health from climate change is relatively small compared with effects of other stressors and is not well quantified.
- Adaptation is an effective means of reducing climate related damages. The benefit-cost ratios of adaptation expenditure are larger than one in all scenarios, and for high and low climate damages and discount rates. Nonetheless, benefit cost ratios, and consequently global welfare, are even larger when adaptation and mitigation are implemented jointly. Even though a clear trade-off between adaptation and mitigation has been quantified, they are strategic complements and both contribute to a better control of climate damages. Mitigation prevails in the short-run and/or if the discount rate is low.
- Differences in vulnerability and exposure arise from non-climatic factors and from multidimensional inequalities often produced by uneven development processes.
- Market adjustments can substantially attenuate initial negative impacts. Nevertheless, equilibrium climate change damages remain substantial at the global level, particularly in developing countries. Accordingly, the distributional and scale implications of climate-related damages must be addressed by adequate policy-driven mitigation and adaptation strategies
- As highlighted in IPCC AR4 (2007), already a moderate warming produces negative consequences: increasing number of people exposed to water stresses, extinction of species and ecosystems, decrease in cereal productivity at low latitudes, land loss due to sea level rise in coastal areas, increase in mortality and morbidity associated to change in the incidence of vector borne diseases or to increased frequency and intensity of heath waves; infrastructural disruption and mortality increase due to more frequent and intense extreme weather event occurrence.
- For most economic sectors, the impacts of drivers such as changes in population, age structure, income, technology, relative prices, lifestyle, regulation, and governance are projected to be large relative to the impacts of climate change
- Economic impact estimates completed over the past 20 years vary in their coverage of subsets of economic sectors and depend on a large number of assumptions, many of which are disputable, and many estimates do not account for catastrophic changes, tipping points, and many other factors. With these recognized limitations, the incomplete estimates of global annual economic losses for additional temperature increases of ~2°C are between 0.2 and 2.0% of income (±1 standard deviation around the mean)
You would be surprised.
Lomborg’s Copenhagen Consensus wrote numbers 1, 3, 5 and 6.
IPCC AR5 WG2 wrote 2, 4, 7 and 8.