Analysis of the Copenhagen Accord pledges and its global climatic impacts—a snapshot of dissonant ambitions

Abstract

This analysis of the Copenhagen Accord evaluates emission reduction pledges by individual countries against the Accord's climate-related objectives. Probabilistic estimates of the climatic consequences for a set of resulting multi-gas scenarios over the 21st century are calculated with a reduced complexity climate model, yielding global temperature increase and atmospheric CO 2 and CO 2 -equivalent concentrations. Provisions for banked surplus emission allowances and credits from land use, land-use change and forestry are assessed and are shown to have the potential to lead to significant deterioration of the ambition levels implied by the pledges in 2020. This analysis demonstrates that the Copenhagen Accord and the pledges made under it represent a set of dissonant ambitions. The ambition level of the current pledges for 2020 and the lack of commonly agreed goals for 2050 place in peril the Accord's own ambition: to limit global warming to below 2 • C, and even more so for 1.5 • C, which is referenced in the Accord in association with potentially strengthening the long-term temperature goal in 2015. Due to the limited level of ambition by 2020, the ability to limit emissions afterwards to pathways consistent with either the 2 or 1.5 • C goal is likely to become less feasible.

Comments on “Why Hasn’t Earth Warmed as Much as Expected?”

“…Their results cannot be reconciled with those presented here based on the Bern2D intermediate complexity climate-carbon cycle model, or indeed with any of the zero emission-commitment or temperaturestabilization scenarios calculated by a climate model that resolves the relevant time scales and reservoirs of the energy balance and carbon cycle (Caldeira et al 2003;Hare and Meinshausen 2006;Weaver et al 2007;Matthews and Caldeira 2008;Plattner et al 2008;Allen et al 2009;Matthews et al 2009;Meinshausen et al 2009;Solomon et al 2009;Zickfeld et al 2009;Frö licher and Joos 2010;Rogelj et al 2010;Solomon et al 2010;Gillett et al 2011).…”

Climate hotspots: key vulnerable regions, climate change and limits to warming

“…1 Illustration of the effect of the current emissions reduction proposals under the Copenhagen Accord. Besides the pathways representing a business-as-usual scenario (BAU very close to SRES A1B, Nakicenovic et al 2000) and the estimated emissions based on the Copenhagen Accord proposals (Rogelj et al 2010a;Rogelj et al 2010b), four low-emission pathways are shown. The black dashed line indicates the expected temperature projections if all global emissions (greenhouse gases and aerosols) would become zero in 2016.…”

Geographical variations in the effectiveness and side effects of deep ocean carbon sequestration

“…[2] To date, mitigation efforts through international political agreements have been slow to reduce greenhouse gas emissions [Rogelj et al, 2010] and stabilizing atmospheric CO 2 will likely require contributions from multiple approaches [e.g., Pacala and Socolow 2004;Royal Society, 2009] [Royal Society, 2009] but both depend on identifying suitable long-term reservoirs. Most attention to date has focused on the potential of geologic storage [Dooley et al, 2006], where CO 2 is injected into depleted oil and gas fields or deep saline aquifers.…”