The Intergovernmental Panel on Climate Change (IPCC) recently published climate change projections to 2100, giving likely ranges of global temperature increase for each of four possible scenarios for population, economic growth and carbon use. We develop a probabilistic forecast of carbon emissions to 2100, using a country-specific version of Kaya’s identity, which expresses carbon emissions as a product of population, GDP per capita and carbon intensity (carbon per unit of GDP). We use the UN’s probabilistic population projections for all countries, based on methods from our group, and develop a joint Bayesian hierarchical model for GDP per capita and carbon intensity in most countries. In contrast with opinion-based scenarios, our findings are statistically based using data for 1960–2010. We find that our likely range (90% interval) for cumulative carbon emissions to 2100 includes the IPCC’s two middle scenarios but not the lowest or highest ones. We combine our results with the ensemble of climate models used by the IPCC to obtain a predictive distribution of global temperature increase to 2100.

Adrian E.Raftery现为美国华盛顿大学统计和社会学教授。作为美国国家科学院院士、美国艺术与科学学院院士及爱尔兰皇家科学院院士，他开创出了新的统计方法来解决社会、环境和健康科学中的问题。他在统计、社会学和其他同行评议的期刊上发表了200多篇文章，被权威科学评价体系Thomson-ISI评为1995-2005年高被引数学家第一名。他已指导29位博士研究生，其中有21位获得大学准聘教职。