The paper reviews analyses of the costs of mitigating climate change and discusses the implications for policy. The estimated effects of reducing carbon emissions by 40%–60% over the next half century range from –1.0% to 4.5% of world product, averaging 2½%. This would be small...

Urban sustainability indicators play an important role in helping policy-makers ensure the continued success of their cities. However, a review of current practice suggests that priority is often given to the measurability and policy relevance of these metrics. Their analytical validity - i.e....