Projects per year
Abstract
Better defining (or altogether avoiding) the term ‘pre-industrial’ would aid interpretation of internationally agreed global temperature limits and estimation of the required constraints to avoid reaching those limits.
The United Nations Framework Convention on Climate Change (UNFCCC) process agreed in Paris to limit global surface temperature rise to ‘well below 2°C above pre-industrial levels’. But what period is ‘pre-industrial’? Some-what remarkably, this is not defined within the UNFCCC’s many agreements and protocols. Nor is it defined in the IPCC’s Fifth Assessment Report (AR5) in the evaluation of when particular temperature levels might be reached because no robust definition of the period exists. Here we discuss the important factors to consider when defining a pre-industrial period, based on estimates of historical radiative forcings and the availability of climate observations. There is no perfect period, but we suggest that 1720-1800 is the most suitable choice when discussing global temperature limits. We then estimate the change in global average temperature since pre-industrial using a range of approaches based on observations, radiative forcings, global climate model simulations and proxy evidence. Our assessment is that this pre-industrial period was likely 0.55–0.80°C cooler than 1986-2005 and that 2015 was likely the first year in which global average temperature was more than 1°C above pre-industrial levels. We provide some recommendations for how this assessment might be improved in future and suggest that reframing temperature limits with a modern baseline would be inherently less uncertain and more policy-relevant.
The United Nations Framework Convention on Climate Change (UNFCCC) process agreed in Paris to limit global surface temperature rise to ‘well below 2°C above pre-industrial levels’. But what period is ‘pre-industrial’? Some-what remarkably, this is not defined within the UNFCCC’s many agreements and protocols. Nor is it defined in the IPCC’s Fifth Assessment Report (AR5) in the evaluation of when particular temperature levels might be reached because no robust definition of the period exists. Here we discuss the important factors to consider when defining a pre-industrial period, based on estimates of historical radiative forcings and the availability of climate observations. There is no perfect period, but we suggest that 1720-1800 is the most suitable choice when discussing global temperature limits. We then estimate the change in global average temperature since pre-industrial using a range of approaches based on observations, radiative forcings, global climate model simulations and proxy evidence. Our assessment is that this pre-industrial period was likely 0.55–0.80°C cooler than 1986-2005 and that 2015 was likely the first year in which global average temperature was more than 1°C above pre-industrial levels. We provide some recommendations for how this assessment might be improved in future and suggest that reframing temperature limits with a modern baseline would be inherently less uncertain and more policy-relevant.
Original language | English |
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Pages (from-to) | 1841–1856 |
Number of pages | 16 |
Journal | Bulletin of the American Meteorological Society |
Volume | 98 |
Issue number | 9 |
Early online date | 24 Jan 2017 |
DOIs | |
Publication status | Published - Sep 2017 |
Profiles
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Philip Jones
- School of Environmental Sciences - Emeritus Professor
- Centre for Ocean and Atmospheric Sciences - Member
- Climatic Research Unit - Member
- ClimateUEA - Member
Person: Honorary, Member, Research Group Member
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Manoj Joshi
- School of Environmental Sciences - Professor of Climate Dynamics
- Tyndall Centre for Climate Change Research - Member
- Centre for Ocean and Atmospheric Sciences - Member
- Climatic Research Unit - Member
- ClimateUEA - Steering Committee Member
Person: Research Group Member, Academic, Teaching & Research
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Timothy Osborn
- School of Environmental Sciences - Professor of Climate Science
- Water Security Research Centre - Member
- Centre for Ocean and Atmospheric Sciences - Member
- Climatic Research Unit - Member
- ClimateUEA - Member
Person: Research Group Member, Research Centre Member, Academic, Teaching & Research
Projects
- 1 Finished
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Securing Multidisciplinary UndeRstanding and Prediction of Hiatus and Surge events (SMURPHS)
Forster, P., Osborn, T., Allan, R., Collins, M., Drijfhout, S., Hegerl, P., Joshi, M. & Sinha, B.
Natural Environment Research Council
1/12/15 → 31/08/20
Project: Research