The Paris emission gap Targets
Paris has come and gone and given us an ambituous temperature target of "well below 2 degrees and pursue efforts of limiting warming to 1.5C" (Art 2). More than that, it also promised Global peaking of emissions as soon as possible, then rapid reductions with best available science, “to achieve a balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases in the second half of this century, on the basis of equity, and in the context of sustainable development and efforts to eradicate poverty.”(Art 4)
Well and good, except the national climate plans submitted by almost all nations, and many of them with conditional clauses, adds up to 2.7C to 3.5C temperature by the end of the century. This is not good. There is an ambition mechanism involving 5 year reviews, but this will still make it hard to meet the goals set out in the Paris Agreement.
- Aviation emissions
- UNEP 2015 Emissions Gap report
- Reduced carbon aerosol pollution will spike warming
- Paris ambition provides some hope
Let's look at some of the charts using the CBAT tool that Aubrey Meyer (twitter) designed and built. You can play around with attributes yourself.
and the carbon budget data table for the graph above:
Increasing Aviation emissions could blow the carbon budget
One of the issues that the Paris Agreement in it's final form did not deal with is the growing emissions from shipping and aviation sector. Aubrey Meyer has modelled what a 5.5 per cent increasing emissions from aviation would look like. It blows our target from all our other action under the Paris Agreement.
Shipping and aviation were dropped between the final draft and the adopted agreement. The issue was highlighted with a fossil of the day award during the Paris conference.
UNEP Emissions Gap Report - November 2015
Here is the UNEP emissions gap report from November 2015 graphic calculated on a 2 degree C target.
The executive summary identifies the gap for 2 degrees C in 2025 and 2030 as:
- The global emission levels consistent with a chance of staying below the 2°C limit, following a least-cost pathway from 2020, 48 GtCO2e (range 46 to 50) in 2025 and 42 GtCO2e (range: 31 to 44) in 2030.
- Emissions are projected to be 54 GtCO2e (range 53 to 58) in 2025 and 56 GtCO2e (range 54 to 59) in 2030, if all unconditional INDCs are implemented. This gives emission gaps of 7 GtCO2e (range 5 to 10) and 14 GtCO2e (range 12 to 17) in 2025 and 2030 respectively.
- If conditional INDCs are included, the global emissions projection is 53 GtCO2e (range 52 to 56) in 2025 and 54 GtCO2e (range 52 to 57) in 2030. This would give emission gaps of 5 GtCO2e (range 4 to 8) and 12 GtCO2e (range 10 to 15) in 2025 and 2030 respectively.
Remember the Paris Agreement has set as a far more ambituous goal well below 2 degrees C and aspire to reach the 1.5C target. Increasing aviation emissions plus the likelihood of climate feedback mechanisms kicking in just adds to the problem.
Reducing carbon pollution aerosols will temporarily increase net warming
The other issue is that as we decarbonize our carbon polluting fossil fuel electricity and transport systems it will reduce the amount of atmospheric particulates and aerosols in the atmosphere. Currently these have a net dampening (cooling) impact on temperatures. As these aerosols and particulates reduce through reduced carbon pollution, temperatures are likely to spike. Z. L. Wang, H. Zhang, and X. Y. Zhang (2015) from the Chinese Academy of Meteorological Sciences and Nanjing University in a paper titled: Simultaneous reductions in emissions of black carbon and co-emitted species will weaken the aerosol net cooling effect (abstract) examine this effect and find their results consistent with other recent studies. Wang et al conclude:
our results suggest that associating with the reduction of net cooling effects directly from aerosols, the aerosol indirect effect is also weakened when emissions of SO2, BC, and OC are simultaneously reduced in different ways to the levels projected for the end of this century under the RCP2.6, RCP4.5, and RCP8.5 scenarios. Relative to the aerosol effect for recent past, the total global annual mean aerosol net cooling effect at the TOA is weakened by 1.7–2.0 W m−2 with the reduction according to potential actual conditions in the emission of all these aerosols (i.e., BC and the major co-emitted species). The main cooling regions are over East Asia, Western Europe, eastern North America, and central Africa, with the largest change exceeding 10.0 W m−2. This is somewhat consistent with the results given by Gillett and Salzen (2013) and Levy et al. (2013), who also reported that the reduction in atmospheric aerosols will weaken the aerosol cooling effect in the future.
Paris ambition provides some hope
If governments do increase their targets and climate plans, then the modelling done by Climate Interactive in December shows that with Improved Pledges Every Five Years, the Paris Agreement Could Limit Warming Below 2°C. I discuss this more in my assessment after the Paris conference concluded: The Paris moment for climate justice and the historic #Parisagreement of #COP21
Emissions Gap in 2011
If we examine the stated commitments of the Copenhagen accord as per June 29 2011 proposals the emissions gap will result in 4.1 degrees C average global warming by 2100. The pledges have reduced business as usual projections by 0.7 degrees from 4.8 degrees C by 2100. The gap is still substantial.
The United Nations Framework Convention on Climate Change (UNFCC) made a commitment at Copenhagen in December 2009 and reaffirmed at Cancun in December 2010 to limit global warming to 1.5 to 2 degrees C temperature goal. But current emission reduction pledges falls far short of achieving this goal according to the United Nations Environment Program Emissions Gap Report.
The Information is beautiful blog has done a great graphic to explain the carbon budget we have:
