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Curbing climate chaos - Why nature is the unsung hero in our quest for net zero

Written by: Annamária Lehoczky

The science is clear. There is no pathway to net zero without nature. Nature loss exacerbates the climate crisis and, in turn, a rapidly heating planet poses a grave threat to the species and habitats that are crucial natural allies in our struggle to keep global temperatures under control. It’s a downward spiral that threatens the very future of life on Earth.

Fauna & Flora’s Senior Technical Specialist on Climate Change, Annamária Lehoczky walks through the key habitats that both hold the answer, and are under threat from climate change.

For decades, the world’s leaders and decision-makers have sat on their hands. A lack of political will, a reluctance to invest in nature, and a failure to engage with the communities living with the everyday realities of climate change have brought us to this point. Most of the so-called ‘Aichi Targets’ – adopted in 2010 in order to address global nature loss – have not been met. Losing biodiversity isn’t just an environmental disaster though. Efforts to achieve the Sustainable Development Goals for poverty, hunger, health, water, cities, climate, ocean and land have also been seriously undermined by negative trends in nature.

We urgently need to scale up efforts to halt biodiversity loss, to protect what’s left, and – where possible – to restore what we’ve lost. It’s a huge challenge, and we’ll need governments, philanthropists and the private sector, among others, to work together towards that common goal, but we already have evidence of how positive action for nature at Fauna & Flora’s project sites around the world is helping to tackle the climate crisis and enhance human well-being.

The forests, grasslands and coastal and marine ecosystems that Fauna & Flora and our partners are working to safeguard are not just biodiversity havens. They also play a vital role in the global carbon cycle by removing it from the atmosphere and storing it for decades, centuries, or even millennia. Between 2007 and 2016 these natural carbon sinks – including terrestrial forests and other, relatively unappreciated, carbon-rich ecosystems – absorbed 28% of total emissions resulting directly from human activities, serving as a hugely significant brake on runaway climate change.

Recent analysis has revealed that at least one billion tonnes of carbon are being locked up in the vegetation and soil of sites protected by Fauna & Flora and our partners around the world. That’s equivalent to the carbon content of eight billion barrels of crude oil – or 23 years’ worth of UK crude oil production.

The findings of this carbon assessment highlight the huge contribution that nature protection makes to slowing human-induced climate change and underline the urgent need to safeguard the countless natural carbon sinks that are in imminent danger of being lost.

Forests – Perennially popular

Forests have been making headlines for decades, often touted as the ‘lungs of our planet’, capable of slowing the alarming global heating rate if only we’d give them a chance. But the carbon sink and storage potential of forests varies greatly across the world’s ecoregions, and even within a forest there are many factors to consider.

Greater tree species diversity within forests has been linked with higher carbon storage in many regions and in recovering forests. A comprehensive study on tropical forests demonstrated that biodiversity has an independent, positive effect on ecosystem functioning, biomass and thus, carbon storage, not only in relatively simple temperate systems but also in structurally complex and extremely species-rich tropical forests.

It is likely that environmental factors such as rainfall and soil conditions are influencing these varying levels of carbon uptake, and tree density and size also play an important role. A forest’s history of disturbance, such as fire, logging or clearance, also affects carbon uptake. In designing and implementing carbon conservation strategies, the prevention of biodiversity loss is therefore paramount.

The rate of carbon sequestration in young forests is higher than in old ones, as young trees are actively growing and absorbing carbon. Over time, the rate of carbon absorption slows, but the economic value of the carbon stored in the ecosystem continues to accumulate as forests mature and increase in size. To retain the benefit of carbon sequestration, forests must be protected and supported to develop into mature, high-carbon-storing forests.

Sapo National Park understorey. © Jeremy Holden / Fauna & Flora

Sapo National Park understorey. © Jeremy Holden / Fauna & Flora

Sapo National Park understorey. Liberia’s Sapo National Park, which Fauna & Flora and partners are working to protect, lies within the biologically rich and globally important Upper Guinea forest ecosystem. It is home to the critically endangered western chimpanzee and African forest elephant, and to the endangered pygmy hippopotamus. Our initial estimates suggest that the park’s species- and carbon-rich ecosystem (covering over 180,000 hectares of mainly intact rainforest) can store a whopping 58 megatonnes of carbon in its vegetation and soil. This is equivalent to the carbon content of almost 500 million barrels of crude oil.

Grasslands – Cinderella syndrome

Grasslands – including savannah – are among the largest ecosystems in the world; some estimates suggest they cover around a third of the global terrestrial surface. Apart from acting as key water catchments and biodiversity havens, grasslands also play a crucial role in reducing global warming, serving as giant carbon sinks that capture carbon and store it underground – hidden from our eyes. Global estimates suggest that grasslands have more than 10% of the biosphere’s carbon tied up in their soil.

Carbon in soil is vital for plants; the vast majority of the nutrients that plants require for healthy growth are acquired via carbon exchange in collaboration with soil microbes. In addition, high-carbon soils require much less irrigation and are less reliant on rain to stay healthy.

Land degradation and conversion threaten these ecosystems and the wildlife they harbour worldwide. Poor land management leads to reduced soil productivity and carbon storage capacity. Planting trees on native grasslands also results in lower soil carbon stocks, which actually reduces or negates the net carbon benefits provided by woody biomass as well as depleting biodiversity. Therefore, experts warn, that afforestation should be avoided in historically non-forested biomes.

Tajikistan grassland. © Alex Diment / Fauna & Flora

Tajikistan grassland. © Alex Diment / Fauna & Flora

Tajikistan grassland. In addition to promoting the protection and sustainable use of Tajikistan’s unique fruit-and-nut forests within Fauna & Flora’s project sites at Childukhtaron and Dashtijum, we also aim to ensure better management of grassland habitats. Between them, the two reserves incorporate around 16,200 hectares of subalpine meadows, with a combined carbon stock estimated to be up to 1.4 megatonnes. Thanks to the dominant soil types and the cool temperate climate, the soils have a high carbon storage potential, accounting for more than 90% of the carbon stored in these mountain grassland ecosystems.

New blue superheroes

Blue carbon is the carbon stored in coastal and marine ecosystems such as mangroves, seagrass meadows and salt marshes. These unsung superheroes sequester and store more carbon per unit area than terrestrial forests – with sequestration rates up to four times greater than those observed in mature tropical forests – and hence are increasingly recognised for their role in mitigating climate change. In these ecosystems, carbon is predominantly (50–99%) stored below ground in the soils and sediments, where it can remain for millennia.

The enormous carbon sink capacity of these ecosystems is the icing on the cake. They also protect against storm surges and sea-level rise, prevent coastal erosion, regulate water quality, provide habitat for commercially important fisheries and endangered marine species, and improve food security for coastal communities.

Some of the most impressive carbon stocks in coastal sediments include mangroves in Belize, which in some places have accumulated carbon-rich soils up to 10 metres deep and more than 6,000 years old. A meadow of seagrass in Portlligat Bay, Spain, has built carbon-rich deposits of similar depth and age. Some tidal salt marsh sediments in northern New England are three to five metres thick and 3,000–4,000 years old. However, when degraded or destroyed, these ecosystems release carbon back to the atmosphere and ocean.

Although their historical extent is hard to determine, up to 50% of the total global area of these ecosystems is estimated to have been lost in the past 50-100 years. If current rates of loss continue (up to 3% annually), a further 30–40% of tidal marshes and seagrasses and nearly all unprotected mangroves could be gone within a century.

Mangrove. © Beth Watson

Mangrove. © Beth Watson

In Honduras, with the support of communities and our in-country partners, Fauna & Flora is contributing to a mangrove monitoring programme throughout two marine protected areas, covering a significant proportion of the 8,500-hectare mangrove found across the seascape in which we work. Initial estimates suggest that the total carbon stock of mangrove forests could be at least 3.2 megatonnes (comparable to carbon content in the UK’s monthly oil production).

Seagrass (Posidonia oceanica) bed, Turkey. © Zafer Kizilkaya

Seagrass (Posidonia oceanica) bed, Turkey. © Zafer Kizilkaya

The slow-growing seagrass Posidonia oceanica plays a vital role in carbon sequestration, but remains under threat from destructive fishing practices including bottom trawling, as well as tourism, coastal development, aquaculture and sand extraction. Seagrass meadows in the Mediterranean are severely depleted; Fauna & Flora is working in Türkiye with local partner Akdeniz Koruma Derneği to build the resilience of the marine ecosystem in the eastern Mediterranean via a network of effectively managed marine protected areas. Assessment of the below-ground soil carbon across sample sites – including intact and degraded seagrass meadows – is helping to inform conservation of existing blue carbon stocks in these delicate habitats.

Peatlands – Hidden talents

Peatlands are found across all climate zones from the tropics to tundra. They occur in various forms, from swamp forests to blanket bog landscapes with open, treeless vegetation, all of which are incredibly rich in carbon – and strongholds of biodiversity. Indeed, peatlands are the largest natural terrestrial carbon store; worldwide, the remaining area of near-natural peatland (over three million square kilometres) contains more than 550 gigatonnes of carbon, exceeding the volume stored in all other vegetation types combined, including forests.

Thanks to year-round waterlogged conditions, dead plants accumulate to form peat, which can become many metres thick, locking in carbon for millennia. In their natural, wet state peatlands help regulate water flow, minimising the risk of flooding or drought, and provide food, fibre and other products that sustain local economies.

However, damaged peatlands – mainly due to drainage, agricultural conversion, burning and mining for fuel – are a major source of greenhouse gases, annually releasing almost 6% of global anthropogenic emissions. Daily emissions from weeks-long fires in Indonesia’s peat swamp forests in autumn 2015 exceeded daily emissions from the entire US economy.

Peat swamp. © Ady Kristanto / Fauna & Flora

Peat swamp. © Ady Kristanto / Fauna & Flora

According to local studies, Indonesia’s vast peat swamps in Sumatra and Kalimantan have been persistent carbon sinks for the past 15,000 years. The resulting peat carbon stores can contain as much as 1,000 tonnes per hectare, with values over 7,500 reported for exceptionally thick (over 12 metres) peat layers. This far exceeds the carbon storage capacity of the above-ground biomass of mature tropical rainforest (typically 130–240 tonnes per hectare). Indonesia’s peat swamps also harbour incredible wildlife, including charismatic species such as critically endangered Sumatran tigers, orang-utans and the weird and wonderful proboscis monkey. Peatland protection and restoration therefore brings significant climate and biodiversity benefits. Working closely with the government, Fauna & Flora is supporting efforts to ensure the remaining peat swamp forest in areas such as West Kalimantan is protected from further degradation as a result of illegal logging, mining activities and fire, and we have also helped set up nurseries to plant seedlings of threatened trees that are unable to regenerate naturally.

Enough is enough

Human pressures, rising global temperatures and increasing climate extremes are threatening to further undermine all these ecosystems’ ability to soak up and store carbon. In order to enable them to play their crucial climate regulation role, we need to prevent further degradation and prioritise their protection and restoration. Rapid, nature-positive decarbonisation is essential if we are to keep warming under 1.5°C and ensure a safe climate where nature and people can thrive.

Annamária Lehoczky profile picture

Annamária Lehoczky

Senior Technical Specialist, Climate Change

Annamária works on climate-proofing Fauna & Flora’s projects, supporting project teams and partners to develop a deeper understanding of climate risk and vulnerability at site level, and to scale up work on ecosystem-based and locally-led approaches to climate adaptation. She holds a PhD in Climate Change, and serves as internal advisor on climate science and on the UN Framework Convention on Climate Change (UNFCCC) processes.