IPCC 1.5 Report: Mitigation pathways clear, but countries need to commit

The IPCC’s Special Report on 1.5°C, published today, offers a stark vision of the choices available to the world in the coming decades. It lays bare the impacts of warming on ecosystems and economies, projects the seriousness of those impacts at 1.5° and 2°C, and how it exacerbates the problems of disadvantaged populations.

It also draws attention to the need for deep cuts in GHG emissions, if we want to avoid the devastating impacts of a 1.5°C-2°C warmer world. The possibilities are two-fold—either we cut emissions fast enough in the next two to three decades to stay on the right side of 1.5°C; or we reduce it less urgently, overshoot the 1.5°C warming threshold by the middle of the century, and then try to decarbonise the atmosphere by the end of the century to drag us back under the threshold. The latter option is rife with uncertainty and increased risks, and will result in higher impacts, adaptation challenges and transitional challenges.

To limit ourselves to 1.5°C with no overshoot, global net anthropogenic CO2 emissions should reduce by about 45 per cent from 2010 levels by 2030, and should reach net-zero around 2050. We also need serious cuts to non-CO2 emissions. Both methane and black carbon need to be reduced by 35 per cent or more of 2010 levels by 2050.

Emission cut across sectors: Challenges and Opportunities

According to the special report, achieving these cuts requires rapid and “far-reaching transitions in energy, land, urban and infrastructure (including transport and buildings), and industrial systems”. There is no silver bullet for deep emission reductions across all sectors. It will require political action and significant scale-up of investment, on a wide portfolio of mitigation options across sectors.

To set us on this pathway, the electricity/energy sector will have to generally meet demand with lower energy use—including through enhanced energy efficiency—and show faster electrification of end use energy. Low-emission energy sources are projected to have a higher share than at present. Renewables, in particular, are projected to supply 70–85 per cent of electricity in 2050.

The IPCC notes that political, economic, social and technical feasibility of solar energy, wind energy and electricity storage technologies has improved substantially over the ­­past few years, signalling a potential system transition in electricity generation. This transition in energy sector will require an investment of around US$900 billion annually, between 2015 and 2050. Average annual investment in low-carbon energy technologies and energy efficiency needs to scale up by roughly a factor of five between 2015 and 2050.

The report also observes that share of nuclear power and “fossil fuels with carbon dioxide capture and storage (CCS)” could increase. For example, the share of gas (with CCS) is estimated at 8 per cent of global electricity generation in 2050. This preservation of fossil fuels is unwelcome. The caveat about CCS is important because it is currently an expensive technology. National rules mandating CCS for all fossil fuel plants will spell disaster. It

The report offers long overdue clarity on coal. It emphasises that use of coal should reduce steeply in all 1.5°C-consistent pathways and its share in electricity mix should be reduced to close to 0 per cent by 2050. The report also indicates the need for a significant fall in the share of oil in energy production by 2050. However, it also observes that 1.5°C-oriented mitigation pathways create risks for regions with high dependence on fossil fuels for revenue and employment generation. At least from a scientific standpoint, therefore, the era of cheap fossil fuels for electricity is over.

The industry sector will have to reduce emissions by around 75–90 per cent of 2010 levels by 2050. The IPCC makes it clear that it is not enough for industry to simply make improvements in energy and process efficiency. Real emission reductions, according to IPCC, can be achieved through a combination of new and existing technologies and practices, including electrification, hydrogen, sustainable bio-based feedstocks, product substitution, and carbon capture, utilisation and storage (CCUS). It also notes that these options are technically proven but their deployment may be limited by economic, financial, human resource and institutional constraints.

The urban and infrastructure system requires changes in land and urban planning practices, as well as deeper emission reductions in transport and buildings. The share of electricity in energy demand in buildings needs to be at about 55–75 per cent in 2050. In the transport sector, the share of low-emission final energy must increase from less than 5 per cent in 2020 to about 35–65 per cent in 2050. The report notes that “economic, institutional and socio-cultural barriers may inhibit these urban and infrastructure system transitions, depending on national, regional and local circumstances, capabilities and the availability of capital.”

In the land-use sector, 0.5–8 million sq km of pasture and 0–5 million sq km of non-pasture agricultural land for food and feed crops needs to be converted into 1–7 million sq km for energy crops. We also need to move from a 1 million sq km reduction in forest area to a 10 million sq km increase by 2050 (relative to 2010). This transition will create challenges in sustainable management of land resources crucial for human settlements, food, livestock feed, fibre, bioenergy, carbon storage, biodiversity and other ecosystem services. Mitigation options for limiting the demand for land include sustainable intensification of land use practices, ecosystem restoration and changes towards less resource-intensive diets, but this would require overcoming socio-economic, institutional, technological, financing and environmental barriers that differ across regions.

We also need to achieve carbon dioxide removal (CDR) to the tune of 100–1000 GtCO2eq over this century, although this is subject to multiple feasibility and sustainability constraints. To minimise the need for this highly uncertain option (to around a few hundred GtCO2eq), we should focus on making significant near-term emission reductions and measures to lower energy and land demand. The role of CDR necessarily increases if we overshoot 1.5°C and then try to decarbonise. The report points out the danger of this approach. We have limited understanding of the effectiveness of net negative emissions ini reducing temperatures after they peak.

As Jim Skea, Co-Chair of the IPCC’s Working Group III repeatedly emphasised during press conference on report’s release - these are the options, the synergies and trade-offs before policy-makers and the general public. The IPCC’s role is limited to bringing forth these options; it is now up to governments to decide on how to act. They can start by scaling up ambition on nationally determined contributions through the Talanoa Dialogue and by agreeing to reporting requirements that will incentivise ambition in the form of a strong Paris Rulebook. Both these processes face critical deadlines at the end of this year. All eyes will now be on the Conference of the Parties (COP 24) in Katowice this December.

COP 24 Katowice Climate Change World

India Environment Portal Resources :

• Global warming of 1.5 °C
• Aggregate emission intensity targets: applications to the Paris Agreement
• Carbon budgets for the 1.5°C limit
• The role of large—scale BECCS in the pursuit of the 1.5°C target: an Earth system model perspective
• Risks from climate extremes change differently from 1.5°C to 2.0°C depending on rarity