Special Report on Emissions Scenarios

The Special Report on Emissions Scenarios (SRES) is a report by the <a href="/facts/Intergovernmental_Panel_on_Climate_Change/sh76du1u">Intergovernmental Panel on Climate Change</a> (IPCC) that was published in 2000. The <a href="/facts/Climate_change_scenario/MCHKP59V">greenhouse gas emissions scenarios</a> described in the Report have been used to make <a href="/facts/Global_climate_model/6QUar9RF">projections</a> of possible future <a href="/facts/Climate_change/rEN4BDE7">climate change</a>. The SRES scenarios, as they are often called, were used in the <a href="/facts/IPCC_Third_Assessment_Report/1DfXFCKF">IPCC Third Assessment Report</a> (TAR), published in 2001, and in the <a href="/facts/IPCC_Fourth_Assessment_Report/s0pDYRt5">IPCC Fourth Assessment Report</a> (AR4), published in 2007. The SRES scenarios were designed to improve upon some aspects of the IS92 scenarios, which had been used in the earlier <a href="/facts/IPCC_Second_Assessment_Report/dh7q9AsV">IPCC Second Assessment Report</a> of 1995. The SRES scenarios are "<a href="/facts/Economics_of_climate_change_mitigation/Bd0As4P0">baseline</a>" (or "reference") scenarios, which means that they do not take into account any current or future measures to limit <a href="/facts/Greenhouse_gas_emissions/Cu9nXPHE">greenhouse gas (GHG) emissions</a> (e.g., the <a href="/facts/Kyoto_Protocol/88twzpDf">Kyoto Protocol</a> to the <a href="/facts/United_Nations_Framework_Convention_on_Climate_Change/Tg7f18g3">United Nations Framework Convention on Climate Change</a>).
Emissions projections of the SRES scenarios are broadly comparable in range to the baseline emissions scenarios that have been developed by the scientific community. The SRES scenarios, however, do not encompass the full range of possible futures: emissions may change less than the scenarios imply, or they could change more.
SRES was superseded by <a href="/facts/Representative_Concentration_Pathways/zoNyvobf">Representative Concentration Pathways</a> (RCPs) in the <a href="/facts/IPCC_Fifth_Assessment_Report/aYz6LE8H">IPCC fifth assessment report</a> in 2014.
There have been a number of comments on the SRES. It has been called "a substantial advance from prior scenarios". At the same time, there have been criticisms of the SRES. The most prominently publicized criticism of SRES focused on the fact that all but one of the participating models compared gross domestic product (GDP) across regions using <a href="/facts/Market_exchange_rate/R4nLyEx1">market exchange rates</a> (MER), instead of the more correct <a href="/facts/Purchasing-power_parity/qpRMGaXG">purchasing-power parity</a> (PPP) approach.

Special Report on Emissions Scenarios open-in-new

Special Report on Emissions Scenarios