Climate Science: UN report highlights need for further global action

CLA Land Use Policy Adviser for Climate and Water Alice Green blogs on the Intergovernmental Panel on Climate Change (IPCC)’s latest report

The UN’s body for assessing the science on climate change have issued a clear warning in their recent publications:

'Climate change is a threat to human well-being and planetary health. Any further delay in concerted anticipatory global action on adaptation and mitigation will miss a brief and rapidly closing window of opportunity to secure a liveable and sustainable future for all'


The Intergovernmental Panel on Climate Change (IPCC) are currently completing their Sixth Assessment Report (AR6). So far this year, two of their working groups have published reports; one looking at adaptation and the latest, published this month (April 2022), looking at mitigation.

What does the IPCC’s Sixth Assessment Report tell us so far?

Despite all the summits, commitments, target setting and international agreements, average annual greenhouse gas emissions during 2010 to 2019 were higher than in any previous decade. Slightly more optimistically, the rate of growth between 2010 and 2019 was lower than that between 2000 and 2009, but there is clearly more to be done – and urgently. Current Nationally Determined Contributions (actions committed to by each country to reduce emissions) announced prior to COP26 would make it likely that warming will exceed 1.5°C during the 21st century.

The problems with fossil fuels are old news, but the action taken globally doesn’t reflect this; the projected cumulative future carbon dioxide emissions over the lifetime of existing and currently planned fossil fuel infrastructure exceed the total cumulative net carbon dioxide emissions in pathways that limit warming to 1.5°C. The transition to low carbon, renewable energy systems is critical if we want to successfully limit warming.

And what about the impacts of warming on farming? Well,

'global warming will progressively weaken soil health and ecosystem services such as pollination, increase pressure from pests and diseases, and reduce marine animal biomass, undermining food productivity in many regions on land and in the ocean’


And these claims aren’t coming from one piece of research; the latest report segment, an assessment of the development of mitigation pathways and their risks, includes information from 18,000 sources, compiled by 278 authors from 65 countries.

The IPCC are clear: without a strengthening of global climate policies, greenhouse gas emissions are projected to rise beyond 2025, leading to a median global warming of 3.2 [2.2 to 3.5] °C by 2100.

Beyond 2°C

The IPCC state with high confidence that at warming levels beyond 2°C, by 2100, risks of extinction and ecosystem collapse escalate rapidly. In terrestrial ecosystems, up to 39% of species assessed will face a very high risk of extinction at 2°C. Beyond average warming of 1.5°C, climate resilient development is progressively harder to achieve because biodiversity and ecosystem services have limited capacity to adapt to increasing global warming levels.

With warming above 2°C, sea-level rise will ‘increase the risk of coastal erosion and submergence of coastal land, loss of coastal habitat and ecosystems and worsen salinisation of groundwater’. At global warming of 4°C, approximately 10% of the global land area is projected to face increases in both extreme high and low river flows in the same location, with implications for planning for water resources. In other words: severe flooding and drought.

The role of land

Land use is key to mitigate climate change. The IPCC found that all the modelled pathways that they assessed that limit warming to 1.5°C or well below 2°C require land-based mitigation and land-use change. Analyses shows that the conservation and protection of 30% to 50% of land, freshwater and ocean areas is needed to maintain the resilience of biodiversity and ecosystem services around the world.

Capturing and storing carbon in nature, for example through afforestation, reforestation, improved forest management, agroforestry and soil carbon sequestration, is the only widely practiced method of removing carbon dioxide. The research also highlights the multiple benefits which such land management practices can deliver: enhancing biodiversity and ecosystem functions, employment and local livelihoods.

While these mitigation options can help to reduce emissions and enhance removals, the IPCC warn that they ‘cannot fully compensate for delayed action in other sectors. Every sector needs to take action to mitigate climate change by reducing emissions and using resources more sustainably.

Even realising the potential from agriculture, forestry and other land use (AFOLU), requires overcoming significant barriers and managing trade-offs. The cost, complexity of agricultural systems, and increasing demands to raise agricultural yields are just a few examples the IPCC cite. They call for more research and development, particularly around emerging technologies to mitigate agricultural methane and nitrous oxide emissions. It is worth noting that despite the potential, UK emissions from agriculture have remained largely stable over the last decade.

Climate finance

Global tracked climate finance has been increasing since the IPCC’s last assessment report (AR5 in 2014) but public and private finance flows for fossil fuels are still greater than those for climate adaptation and mitigation. We need annual investment three to six times greater than current levels between 2020 and 2030 to limit warming to 2°C or 1.5°C.

Agriculture, forestry and other land use (AFOLU) is one of the sectors with the widest mitigation investment gap in relative terms. The IPCC point to policies which recognise interaction with wider ecosystem services to enable further finance – both public and private – for land-based mitigation. In the UK, we are starting to move in this direction, with the government’s Environmental Land Management scheme supporting public money for public goods, as well as emerging markets for carbon and biodiversity net gain credits.

Although carbon credits and emissions trading are sometimes criticised, the IPCC’s research found that there is no consistent evidence that current emission trading systems have led to significant emissions leakage. Emissions leakage is where there is an increase in emissions elsewhere due to changes to reduce emissions locally.

What’s next?

The IPCC’s full synthesis report won’t be published until later this year, but there is clearly no time to waste. We need enhanced monitoring, reporting and verification capacity to support land-based mitigation, increased public and private finance flows globally and a phase out of fossil fuel.

The next decade is key for the climate.

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