LIMITING global warming to 1.5°C requires rapid and unprecedented changes to society, UN climate experts have warned policymakers in a follow up to the 2015 Paris Climate Agreement.
The report was unveiled today at a meeting of the UN Intergovernmental Panel on Climate Change (IPCC) in South Korea, following a request at the signing of the Paris Climate Agreement that experts conduct an assessment on limiting a global rise in temperatures to 1.5°C above pre-industrial levels.
After reviewing more than 6,000 scientific papers and 42,000 expert and government comments, the authors warn that “rapid and far-reaching” transitions in land, energy, industry, buildings, transport, and cities are needed to hit the target.
A climb of half a degree in warming from 1.5°C to 2°C will likely lead to sea levels rising by an extra 10 cm by 2100. The IPCC warns that a higher rise will hit ecosystems harder, for example by increasing ocean acidity, reducing fish stocks and virtually wiping out coral reefs.
Human-caused emissions of CO2 will need to fall by around 45% from 2010 levels by 2030, reaching net zero around 2050. Though the experts warn the scale of changes required have no documented historic precedent.
“Limiting warming to 1.5ºC is possible within the laws of chemistry and physics but doing so would require unprecedented changes,” said IPCC working group co-chair Jim Skea.
The experts report that overall emissions can be reduced faster through measures that produce less emissions rather than relying on technologies that remove CO2 from the atmosphere. However, if society fails to make these changes and we overshoot 1.5ºC, then there will be greater need to apply such techniques. The two most common methods of carbon dioxide removal (CDR) in the IPCC’s ‘1.5ºC pathways’ are bioenergy with carbon capture and storage (BECCS) and afforestation. However, the report concedes that such techniques are unproven at scale and may carry significant risks of their own when it comes to sustainable development.
“CDR deployed at scale is unproven and reliance on such technology is a major risk in the ability to limit warming to 1.5°C,” the authors write. “CDR is needed less in pathways with particularly strong emphasis on energy efficiency and low demand.”
It will come as little surprise that more renewable energy will be needed and less coal burned to hit the 1.5°C target. The share of primary energy from renewables including hydroelectric power will need to grow from around 10% in 2017 to 49-67% by 2050.
Industry has room for gains in energy efficiency, with the recovery and reuse of waste heat flagged as a viable option. However, it warns that without major deployment of low-carbon industrial processes, climate targets are difficult to achieve.
“Bringing such technologies and processes to commercial deployment requires significant investment in research and development. Some examples of innovative low-carbon process routes include: new steelmaking processes such as upgraded smelt reduction and upgraded direct reduced iron, inert anodes for aluminium smelting, and full oxy-fuelling kilns for clinker production in cement manufacturing,” the authors write.
Industry contributes around 25% of total energy-related and process CO2 emissions, and these have increased on average 3.4% per year between 2000 and 2014, which is significantly faster than total CO2 emissions.
The report acknowledges that CCS will play a crucial role in decarbonising industry especially those with higher process emissions, such as cement, iron and steel industries. The development and demonstration of projects has been slow, with only two large-scale industrial CCS projects in operation outside of the oil and gas industry, and is hampered by long lead times on projects.
Brad Page, CEO of the Global CCS Institute, said the IPCC’s report reconfirms the role that CCS must play in mitigating climate change and decarbonising industry, particularly the high-emitting cement, steel and petrochemical sectors.
“These are sectors that cannot be turned off at the flick of a switch. They need a technology that can mitigate their emissions at the same time as safeguarding the jobs and economies they support.”
Making the transition will require policies that put a high price on emissions, that increase investments in low-emission infrastructure and scrap regimes that subsidise fossil fuel use. While transitions in energy systems are taking place and the renewables technology is improving, the IPCC warns that to meet the target “almost all countries would need to significantly raise their level of ambition”.
“The political, economic, social and technical feasibility of solar energy, wind energy and electricity storage technologies has improved dramatically over the past few years, while that of nuclear energy and CCS in the electricity sector have not shown similar improvements.
“Electrification, hydrogen, bio-based feedstocks and substitution, and in several cases carbon dioxide capture, utilisation and storage (CCUS), would lead to the deep emissions reductions required in energy-intensive industry to limit warming to 1.5°C. However, those options are limited by institutional, economic and technical constraints, which increase financial risks to many incumbent firms,” the authors write.
Responding to the report, Richard Betts, head of climate impacts research at the Met Office, said: “The report shows that we now risk being stuck between a rock and a hard place if we don’t take the right courses of action. Crucially, the report discusses pathways that aim to limit warming to 1.5°C without making poor and disadvantaged people worse off. The report also notes that many proposals to avoid the risks of 2°C warming could, if done badly, threaten food security by using land for afforestation and bioenergy in the wrong way.
“Some climate change impacts, such as a certain amount of sea level rise, are already locked-in for the long term and will require adaptation, especially in vulnerable countries. Limiting warming to 1.5°C would help limit these impacts and reduce the risk of them becoming unmanageable, but doing this effectively and fairly without causing other problems is a huge challenge.”
Dave Reay, professor of carbon management at the University of Edinburgh, said: “None of the pathways that can lead the world to a safer, ‘1.5 degree’ future is easy. All require seismic changes in our energy, food, housing and transport systems. Some rely on unproven ‘negative emission’ technologies – like large-scale direct capture of carbon dioxide from the air – to claw our way back to a safer climate should we overshoot.
“The strapline to this whole special report could arguably be that hackneyed advice to lost travellers ‘If you want to get there, I wouldn’t start from here’. But here we all are. With each year that rolls by without global emission cuts so our opportunities to avoid dangerous climate change diminish.
“The IPCC have shown us what could be, the world must now decide what will be.”
The report will feed into future international climate negotiations, including the next annual UN climate summit in Poland in December.
It follows an analysis by the Royal Academy of Engineering and Royal Society published in September that set out a series of urgent recommendations that would allow the UK to achieve its target of net-zero carbon emissions by 2050 that relied heavily on the use of technologies that remove emissions from the atmosphere.
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