The nature and climate crises are inexorably interlinked. Changes in climate affect nature, while investing in nature can help people to both mitigate and adapt to climate change. That is why there has been a massive effort to make links between biodiversity COP 15 and climate COP 26. In today's blog, hear about the latest research contributing towards our understanding of climate change mitigation, from our team of scientists.

At the RSPB Centre for Conservation Science, we have been contributing to the evidence on how climate impacts nature, and how we can help nature to adapt. We have also been looking at how ‘nature-based solutions’ (NbS) can contribute to mitigating climate change, as well as providing a range of other societal and economic benefits. Our work ranges from the scale of fields to the globe.

Farming can work for climate

At the small scale, we’ve been looking at solutions in intensive agricultural systems that work for both nature and climate, while supporting resilient continued agricultural production.

Within fields, our cover crop and compost trial at Hope Farm showed the addition of municipal compost to agricultural soils increases soil organic carbon and promotes earthworm activity (a key ‘soil health’ indicator). Cover crops, intended to protect soils from erosion and compaction, also promotes invertebrate abundance and diversity, in turn benefiting winter feeding birds. We are now beginning an exciting investigation of the benefits of agroforestry.

Agroforestry field at Hope farm growing spring oats around wildflower strips ready for tree establishment this winter © Sophie Mott

We also showed that our whole farm strategy to increase bird populations without compromising farming profitability was beneficial for reducing GHG emissions. For many years, we have worked with academic researchers to improve the understanding of how peatland damage and restoration affects not only nature but also GHG emissions.

UK-wide

At the national scale, we have been most interested to see what contribution nature can make to achieving national carbon reduction targets in the UK. We first used satellite-derived mapping to locate all the areas in the UK that provide special habitats for nature– species-rich grasslands, ancient woodlands, saltmarshes, heaths and bogs. We showed that they collectively store around 500 Gigatonnes of carbon in their soils and vegetation already removed from the atmosphere by photosynthesis.

Moreover, we estimated that these nature-rich habitats draw a further 2.2 million tonnes of carbon out of the atmosphere each year – equivalent to the annual emissions of 4 million cars (12% of all the UK’s cars). This figure could be much higher, if the condition, particularly of peatlands, were better; they have the potential to draw down as much as 4 million tonnes a year, if cared for better.

Nature based solutions for climate

Then we built on that work by exploring in detail the potential of three NbS measures for additional climate change mitigation in the UK over the rest of this century. We calculated the potential reduction in emissions from peatland restoration and levels of sequestration from woodland and saltmarsh creation, following scenarios proposed by the CCC.

Forsinard Flows in Scotland is an example of peatland being restored (c) Andy Hay (rspb-images.com)

One immediate concern was whether there would be enough land available for new woodland. We determined there would be just enough land potentially available for the CCC’s most ambitious woodland creation scenarios (almost 2 million hectares), while minimising impacts on agricultural production and biodiversity.

By the end of the century, ambitious roll-out of these three NbS could mitigate the equivalent of three years’ worth of the UK’s total current emissions. Though this might be proportionately lower than the considerable role suggested for NbS globally, it is still a significant chunk in the context of a country with high population density and high per capita emissions from key sectors such as transport, housing and industry.

International work

Obviously, climate change is global and, RSPB work extends beyond the UK. RSPB has a large geographic focus on west Africa, an area of global conservation importance for biodiversity and one of the areas under greatest pressure from human activities. In addition to being a home of many endemic species, it supports the populations of many Afro-Palearctic migrants during the non breeding season.

Recent analysis by RSPB, accepted for publication in the journal Carbon Management, estimated that the vegetation and top layers of soil in the region contained 38,855 Mt of carbon.

Figure 1. Total estimated carbon in above and below ground vegetation and the top 30 cm of soil in the Guinean forest ecoregion of west Africa in 2010. Key Biodiversity Areas are shown by solid black lines, country borders by dashed lines.

This is a major store of carbon, and we estimates sequesters between 23.6 and 53.6 Mt of carbon a year. This level of sequestration is around 30% of projected emissions from the countries of the region, based on existing national climate change pledges.

Key Biodiversity Areas, which are sites of high conservation importance, cover 7.4% of west Africa, but contain 12.1% of the carbon and sequester 16.6% of carbon, meaning these sites of crucial conservation importance punch above their weight in terms of carbon storage. However, the carbon stored in vegetation in west Africa is not safe.

Our project area in Gola © Caroline Thomas (rspb-images.com)

Our analysis indicated that trees containing 672 Mt of carbon were lost between 2010 and 2018.  Ongoing tree cover loss is a major cause for concern in the region as it will impact biodiversity and carbon storage and sequestration. RSPB are working with local communities in and around Gola to develop ways to secure their livelihoods in ways that minimise the impact on remaining forest.

Trade-offs between mitigation and biodiversity

As the global understanding of the volumes of carbon stored within vegetation increase, together with our ability to map land cover at a global scale, we, along with collaborators from across the globe including Cambridge University, Oxford University, and BirdLife International are able to estimate the synergies and trade-offs between actions aimed to mitigate against climate change and restore biodiversity.

We are in the process of completing a global analysis looking at just these synergies and trade-offs, quantifying the biodiversity and carbon storage implications of restoring natural vegetation or plantation forests across the globe, whether to maximise carbon storage or restore the most important areas for biodiversity.

This work uses a number of existing scenarios to illustrate the synergies and trade-offs for climate and biodiversity, as well as establishing a method for RSPB and others to rapidly assess the impacts of future scenarios. We continue to work with science colleagues in BirdLife International and elsewhere to ensure RSPB, and global, policy is based on the best available evidence.

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