Tracking uncertainties in the causal chain from human activities to climate

Sarah C B Raper,Chris Pires De Campos,Michael J Prather,Niklas Höhne,Luiz Pinguelli,Ragnhild B Skeie,Jason A Lowe,Fabian Wagner,John Van Aardenne,Joyce E Penner,Natalia Andronova,Peter A Stott,Atsushi Kurosawa,Atul K Jain,Jan S Fuglestvedt

doi:10.1029/2008gl036474

Abstract

Attribution of climate change to individual countries is a part of ongoing policy discussions, e.g., the Brazil proposal, and requires a quantifiable link between emissions and climate change. We present a constrained propagation of errors that tracks uncertainties from human activities to greenhouse gas emissions, to increasing abundances of greenhouse gases, to radiative forcing of climate, and finally to climate change, thus following the causal chain for greenhouse gases emitted by developed nations since national reporting began in 1990. Errors combine uncertainties in the forward modeling at each step with top‐down constraints on the observed changes in greenhouse gases and temperatures. Global surface temperature increased by +0.11 °C in 2003 due to the developed nations' emissions of Kyoto greenhouse gases from 1990 to 2002. The uncertainty range, +0.08 °C to +0.14 °C (68% confidence), is large considering that the developed countries emissions are well known for this period and climate system modeling uncertainties are constrained by observations.

Highlights

[1] Attribution of climate change to individual countries is a part of ongoing policy discussions, e.g., the Brazil proposal, and requires a quantifiable link between emissions and climate change
[2] A wide range of human activities are responsible for greenhouse gas (GHG) emissions and are designated for national reporting under the National Greenhouse Gas Inventories Programme (NGGIP) of the Intergovernmental Panel on Climate Change (IPCC) [1997]
[3] Scientific study of the relative amount of climate change that could be attributed to national emissions was stimulated by Brazil’s proposal to the UNFCCC [Filho and Miguez, 1998] in which commitments to reduce GHG emissions would be based on the developed (Annex-I) nations’ historical contribution to climate change

Summary

Tracking uncertainties in the causal chain from human activities to climate

We present a constrained propagation of errors that tracks uncertainties from human activities to greenhouse gas emissions, to increasing abundances of greenhouse gases, to radiative forcing of climate, and to climate change, following the causal chain for greenhouse gases emitted by developed nations since national reporting began in 1990. Errors combine uncertainties in the forward modeling at each step with top-down constraints on the observed changes in greenhouse gases and temperatures. Global surface temperature increased by +0.11 °C in 2003 due to the developed nations’ emissions of Kyoto greenhouse gases from 1990 to 2002. The uncertainty range, +0.08 °C to +0.14 °C (68% confidence), is large considering that the developed countries emissions are well known for this period and climate system modeling uncertainties are constrained by observations.

Introduction

Findings

Discussion