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How Much Human-Caused Global Warming Should We Expect with Business-As-Usual (BAU) Climate Policies? A Semi-Empirical Assessment
- Source :
- Energies, Vol 13, Iss 6, p 1365 (2020)
- Publication Year :
- 2020
- Publisher :
- MDPI AG, 2020.
-
Abstract
- In order to assess the merits of national climate change mitigation policies, it is important to have a reasonable benchmark for how much human-caused global warming would occur over the coming century with “Business-As-Usual” (BAU) conditions. However, currently, policymakers are limited to making assessments by comparing the Global Climate Model (GCM) projections of future climate change under various different “scenarios”, none of which are explicitly defined as BAU. Moreover, all of these estimates are ab initio computer model projections, and policymakers do not currently have equivalent empirically derived estimates for comparison. Therefore, estimates of the total future human-caused global warming from the three main greenhouse gases of concern (CO2, CH4, and N2O) up to 2100 are here derived for BAU conditions. A semi-empirical approach is used that allows direct comparisons between GCM-based estimates and empirically derived estimates. If the climate sensitivity to greenhouse gases implies a Transient Climate Response (TCR) of ≥ 2.5 °C or an Equilibrium Climate Sensitivity (ECS) of ≥ 5.0 °C then the 2015 Paris Agreement’s target of keeping human-caused global warming below 2.0 °C will have been broken by the middle of the century under BAU. However, for a TCR < 1.5 °C or ECS < 2.0 °C, the target would not be broken under BAU until the 22nd century or later. Therefore, the current Intergovernmental Panel on Climate Change (IPCC) “likely” range estimates for TCR of 1.0 to 2.5 °C and ECS of 1.5 to 4.5 °C have not yet established if human-caused global warming is a 21st century problem.
- Subjects :
- Control and Optimization
010504 meteorology & atmospheric sciences
Energy Engineering and Power Technology
Climate change
010502 geochemistry & geophysics
01 natural sciences
paris agreement
lcsh:Technology
Business as usual
climate change mitigation
Empirical assessment
climate policies
business-as-usual
Electrical and Electronic Engineering
Engineering (miscellaneous)
0105 earth and related environmental sciences
Renewable Energy, Sustainability and the Environment
lcsh:T
airborne fraction
Global warming
Climate change mitigation
Climatology
General Circulation Model
Greenhouse gas
Climate sensitivity
Environmental science
climate sensitivity
Energy (miscellaneous)
Subjects
Details
- Language :
- English
- ISSN :
- 19961073
- Volume :
- 13
- Issue :
- 6
- Database :
- OpenAIRE
- Journal :
- Energies
- Accession number :
- edsair.doi.dedup.....0939e005a5f8e9037a70bd0e2c0279c0