Trees draw carbon dioxide from the atmosphere and store it, turning the captured carbon into building blocks for their roots, trunks and branches. Trees also cool the air with moisture and shade, and could reduce temperatures by up to 4% in urban areas. Trees are highly effective carbon banks, and the beauty is that they are self-generating, cost very little, and in many cases they don’t even need to be planted. Allowing trees to regenerate naturally from scrub often results in forests which are more resilient against drought and disease. Research suggests that this approach would store around 400 tonnes of carbon per square kilometre every year, as well as providing improved flood
protection.

Grasslands store carbon dioxide in the soil, and they are particularly effective when the ground is rich in plant diversity. A number of our nature reserves comprise of species-rich grassland, including St Catherine’s Hill in Winchester and Arreton Down on the Isle of Wight. Not only are these reserves contributing to a wider network of carbon dioxide absorbing grasslands, they provide habitat for invertebrates and other wildlife. At Barton Meadows nature reserve in Winchester we have reverted arable fields (which are net carbon emitters) to wildflower meadows (which are net absorbers), and are noticing increased soil invertebrate populations as well as a surge in pollinating insects. Combined, these nature reserves cover over 97 hectares of land, capable of locking away around 11,000 tonnes of carbon.

Floodplains are areas of grassland adjacent to rivers where flooding may occur, and they are hugely valuable as carbon traps. Winnall Moors, which covers around 160 acres, could offset one passenger’s share in nearly 1,000 return flights from Southampton to Newcastle each year! Moreover, floodplains store significant amounts of water; the Rivers Test and Itchen were once connected to their floodplains, the loss of which contributed to the serious floods of 2014. Floodplains are capable of retaining up to five times more water throughout the year compared to improved grasslands, which are managed to increase productivity (usually through ploughing or herbicide use). Creating joined-up networks of healthy floodplain meadows across the landscape could mitigate soil erosion and pollution, and prevent serious flooding in the future.

The UK’s peatlands store around 3.2 billion tonnes of carbon, and we get 70% of our drinking water from peatland river catchments. Sadly, more than 94% of the UK’s lowland peat bogs have been destroyed or damaged, and this vital habitat isn’t easily replaced: peat takes thousands of years to form. In order to perform all of its essential functions, peat must be wet, so the degradation of our river systems and wetland habitats has terrible implications for this valuable natural resource. Hampshire and the Isle of Wight are home to nationally important peat beds, some of which sit within the boundaries of our nature reserves. The Eastern Yar River Valley, for example, contains some of the deepest peat deposits in southern England. We are working with our partners to restore floodplain habitats, improving them for wildlife and enhancing their peat-building capacity.

If a seagrass bed remains undisturbed, it can trap vast amounts of carbon for hundreds of years. This is partly because most of the carbon is trapped within plants and algae, which release some of their trapped carbon when they die and decompose. Decomposition happens more slowly under the sediment, so once carbon is locked in it can stay that way for longer. Salt marshes are also highly effective at sequestering carbon. When marshland plants die they are buried in the mud, rather than decomposing and releasing carbon into the atmosphere. Lymington and Keyhaven Marshes nature reserve on the New Forest coast is a fantastic example of a thriving salt marsh. Sadly, this precious habitat and others like it are eroding at a terrifi c rate due to sea level rise. However, securing new low-lying land adjacent to sites like Lymington and Keyhaven Marshes would prolong their lifespan and create additional habitat, and we are always on the lookout for opportunities to purchase suitable sites.