A new paper published today and led by RSPB scientists explores some of the likely consequences of changing UK land use to meet greenhouse gas emission reduction targets. By modelling nine future scenarios of future land use, the study shows that a net zero UK land sector is possible, but requires a strategic and carefully-planned approach. Lead author Tom Finch, Senior Conservation Scientist explains.
Land has the potential to sequester and store carbon and so contribute to efforts to reduce climate change. Photosynthesis presents a ready-made solution, without need for investment in expensive R&D. Unfortunately, the way we currently use land in the UK results in a net emission of greenhouse gases, equivalent to something like 12% of the UK’s total greenhouse gas emissions. These emissions mainly come from agriculture and drained peatlands.
Aerial photograph of RSPB Labrador Bay Nature Reserve (c) Matt Self (rspb-images.com)
We know that to reduce these emissions, the way we use land needs to change. In 2020, the Climate Change Committee (CCC) outlined a range of ‘net zero’ scenarios for the land sector. These pathways saw a 19-39% reduction in the area of cropland and a 25-63% reduction in the area of grassland by 2050.
But land isn't just about carbon or greenhouse gases. Society also relies on land to provide most of our food and all of our timber. And of course, in addition to the climate crisis, we have an enduring nature crisis which is strongly linked to our use of land.
Our paper builds on the CCC's 2020 analysis by 1) representing scenarios as high resolution spatially explicit maps of the UK (2) considering potential impacts on >100 breeding bird species and (3) introducing additional measures like semi-natural grassland creation, wood pasture and organic farming.
We explored 9 scenarios. One involved no attempt to reduce emissions from the land sector. Two were based on the CCC scenarios Balanced Net Zero Pathway and Widespread Engagement. The rest saw either more or less ambitious deployment of measures aimed at reducing emissions from the land sector including ‘nature-based solutions' like woodland creation and peatland restoration.
We turned each scenario into a map, according to some simple but carefully-considered assumptions about which measures should be promoted/avoided in certain places.
The graph shows the change in GHG emissions (compared to 2015=1.0, net zero from land sector=0.0) under each scenario on the horizontal axis. The vertical axis shows the change in the bird habitat index (left), food production (centre) and timber and biomass fuel production (right). Scenarios which reduce GHG emissions tend to increase bird habitat availability but reduce food production.
When we designed each scenario, we didn't know for sure whether they'd actually deliver a net zero land sector. As it happens, four scenarios – those with most ambitious deployment of nature-based solutions – came close to, or actually achieved, net zero by 2050.
Our modelling suggest that birds will, on average, see increases in habitat availability under these high-performing mitigation scenarios. But there are losers (especially farmland birds) among the winners (especially woodland birds).
The big trade-off is with agricultural production, which we predict will decline by 21% under the best performing mitigation scenario. This reduction is bigger for animal-based products than plant-based products, because our scenarios avoid certain measures taking place on productive croplands.
By 2050, timber production is still broadly similar between scenarios – it takes time for new forests to reach maturity. Differences are greater by 2100, as well as for near-term biomass fuel production. But there isn’t such a strong ‘co-benefit’ (as for birds), or ‘trade-off’ (as for food production) between timber production and emissions savings.
Impact on the UK land sector
So, what does this mean? Our work suggests it is possible for the UK land sector to achieve net zero by 2050 thus making an important contribution to the UK’s wider net zero target. And by doing so we would probably benefit birds. But such widescale land-use change raises many questions and challenges around how and where land use should change, and about the consequences of that change for local communities and land managers. These changes need to be discussed, debated and deployed in ways that are smart, strategic, democratic and just.
The impact on agricultural production shouldn’t be surprising given the measures the CCC use to ‘release land’ (predominantly yield growth, food waste reduction and dietary change). But this isn't about pitting climate action or nature restoration against ‘food security’. Yes, there are some tricky trade-offs, but (1) we can mitigate reductions in production by some combination of wasting less food, feeding fewer crops to animals, and sustainable yield increases; and (2) slowing and reversing climate change and nature loss will ultimately benefit food security.
It's worth recognising that a net zero land sector is arguably a soft target. We're unlikely to get fossil emissions down all the way to zero, so land should ideally be net negative – at least in the absence of affordable and effective engineered greenhouse gas removal technology.
We also want to make clear that the 9 scenarios we explored in this study aren’t an exhaustive list of all possible futures for UK land-use. Other futures, modelling frameworks and assumptions are available! But we think that the big picture messages emerging from this work are robust, and – critically – they align with other independent studies.
What does this mean for our land-use policy? Find out in the blogs below
Continue reading
Would you like to be kept up to date with our latest science news? Email with the heading 'enewsletter' to be added to our quarterly enewsletter.
Want our blogs emailed to you automatically? Click the cog in the top right of this page and select 'turn blog notifications on' (if you have an RSPB blog account) or 'subscribe by email'.