The IPCC will be launching another report on Monday 4 April. This report covers the mitigation of climate change, basically how governments and leaders deliver on the promises made at the UNFCCC Paris COP21, and what should be done and when, in order for the best chance of limiting global temperatures as close to 1.5c as possible. It is being led by IPCC Working Group III, and negotiations began on Monday 21 March.
The Working Group III (AR6 WGIII) report will be the most comprehensive review of how we can mitigate climate change – since the I 5th assessment (AR5) in 2014, and the IPCC’s three recent special reports (SR1.5 in 2018 and the 2019 SRCCL and SROCC).
The report will be ratified after a plenary negotiation in which governments formally approve the summary for policymakers, ensuring high credibility in both science and policy communities. The outline is already approved, and the report will cover a broad spectrum of topics, from mitigation pathways and in-depth sectoral analysis to finance, international cooperation, net-zero and carbon dioxide removal. For the first time in IPCC history, chapters dedicated to technology, innovation and demand-side measures are included.
This briefing covers some of the major developments in our knowledge of mitigation since the IPCC’s AR5 was published in 2014. Today, mitigation literature largely reflects the 2015 Paris Agreement, increasing net-zero commitments and the growing need for action from non-governmental stakeholders including businesses, industry and financial institutions.
Since greenhouse gas emissions have continued to climb We are nowhere near on track to achieve the Paris targets of keeping warming below 2°C, and ideally 1.5°C. Current national climate plans (NDCs) will see us warm by about 2.7°C this century, or possibly even higher.
If CO2 emissions continue at current rates, we will exhaust the remaining 1.5°C carbon budget in the early 2030s. The energy infrastructure from planned and current fossil fuels alone commits us to about 846 GtCO2 (more than double what’s left in our 1.5°C carbon budget) and every year we add more carbon-intensive infrastructure than we decommission.
Of the greenhouse gases (GHGs), CO2 causes most warming due to its high concentration and long lifetime in the atmosphere. Despite efforts to reduce emissions, our burning of fossil fuels adds more CO2 to the atmosphere, pushing the cumulative atmospheric concentration to unsustainable highs. Between 1850-2019, coal, oil and gas accounted for ~66% of cumulative CO2 emissions, with land-use change responsible for about 32%.
But since then, there has been greater recognition of increasing emissions of methane (CH4) and nitrous oxide (N2O). Both are potent GHGs that trap about 34 and 300 times more heat than CO2 respectively (over a 100 year period). Methane is responsible for almost a quarter of human-caused warming to date, and concentrations are increasing faster now than at any time since the 1980s. Today, methane emissions are two-and-a-half times above pre-industrial levels. The AR6 WGI SPM authors emphasised that “strong, rapid and sustained reductions” in methane emissions would have the dual impact of limiting “the warming effect resulting from declining aerosol pollution” and improving air quality.
Between 2008-2017, agriculture and waste contributed most to the rise, followed by the fossil fuel industry. However, estimating by exactly how much, and from where, methane emissions are increasing is a topic of continued research and debate. For example, some researchers have found that the role of North American shale gas (so called “fracking”) has been significantly underestimated in calculating the global methane emissions.
Emissions of N2O have risen 20% from pre-industrial levels, with the fastest growth observed in the last 50 years, mainly due to nitrogen additions to croplands through fertilisers. In 2018, global GHG emissions were about 57% higher than in 1990 and about 43% higher than in 2000. Emissions continued to rise in 2019, when they reached about 59 GtCO2e. But in 2020, the COVID-19 pandemic led to a historical large drop in CO2 emissions from fossil fuels and industry. During the height of global lockdowns, daily emissions dropped by 17% compared to 2019, levels not seen since 2006, and people around the world were allowed a short respite from deadly air pollution. Since then, emissions have rebounded, and were the highest yet last year. However, research has shown that rebuilding the economy in a more green, sustainable, just and climate-centred way represents a far greater opportunity than the short, lockdown-triggered emissions break, which will have little impact in the long run.
The writer of this article is Dr. Seema Javed, a known Environmentalist, Journalist and Communications Expert