Flora and fauna at risk by march of global warming
SOME of us could be forgiven for thinking that after the miserably cold and wet summer, a bit of global warming wouldn’t be a bad thing. Sadly, however, it doesn’t work like that. Our climate is becoming more unpredictable with increasingly frequent and extreme weather events such as heat-waves, heavy rainfall, drought and high winds.
Current indications under the UK Climate Projections 2009 are that by the 2080s, Scotland will be warmer, especially in summer. Snowless winters may become the norm in some parts: they may get wetter and summers generally drier. Scotland’s growing season may increase by 20–80 days. On the face of it, that doesn’t seem too bad. However, for biodiversity, there are likely to be winners and losers.
Climate change has already caused earlier spring events such as trees budding, birds migrating and egg laying. But if species adapt at different speeds, this can affect their survival. For example, caterpillars may emerge earlier than birds’ eggs hatch, leading to a lack of food for some bird chicks. Shifts in the range of plant and animal species have already been recorded, particularly northwards, and there are new species moving to Scotland such as the comma butterfly.
Scottish species confined to mountains may be lost as conditions become unsuitable or other species replace them. Some may become extinct if they are unable to adapt to a rapidly changing environment. And, when combined with associated disturbances such as flooding, landslips and an increase in pests, there could be major changes to ecosystems and the relationships between species.
The most obvious changes in Scotland may be to coastal, marine and freshwater ecosystems. Increasing amounts of greenhouse gases in the atmosphere lead to increasing global average air and surface sea temperatures, widespread melting of snow and ice, and rising sea levels. As sea levels rise, salt marsh and sand dunes will be lost where man-made features or the natural landscape prevents them moving inland. The oceans are becoming more acidic as increasing levels of atmospheric carbon dioxide react with sea water.
In the seas around Scotland, there have already been shifts in ranges in algal, plankton and fish abundance. Rivers may become more affected by low flows in summer and by flash floods in winter washing out spawning beds for salmon. Wetlands may dry out in summer allowing woody species to colonise or causing peat to erode with consequences for carbon dioxide emissions.
Nature and landscapes will clearly be affected by climate change but they can also help us play our part in global efforts to reduce emissions and to adapt. We can manage woodlands and peatlands to store carbon for us. More than 400 million tonnes of carbon is estimated to be stored beneath the surface of the flow country of Caithness and Sutherland – carbon that would otherwise be released to the atmosphere and contribute to global warming. This is estimated to be more than two times more carbon than all the UK’s plants and forests put together.
The natural environment can provide services that we rely upon, such as providing water supplies and reducing flood risks. Providing a nationwide network of healthy habitats can also help wildlife disperse into new areas as the climate changes and also create better places for people to live in and enjoy.
We will be promoting actions for us all to consider in the years to come. These include ensuring that effective management of the sea and land ‘locks up’ carbon by promoting activities which reduce carbon loss and increases the amount of carbon stored in vegetation and soils. Restoring peat-forming habitats which have been drained or damaged, such as those in the flow country, is a focus for our work locally.
In the north, many of our native woodlands lack regeneration and this threatens their long-term survival. Bare peat caused by trampling or muirburn on blanket bog can lead to serious erosion and oxidation of peatland soils, increasing carbon dioxide discharges. We can also help the environment adapt by enhancing the natural capacity of catchments – the soils, vegetation, river floodplains and wetland habitats, to reduce flood risk. The use of trees, shrubs and other plants around buildings and in public open spaces can provide shade and reduce energy demands for cooling and insulating purposes.
We are also committed to strengthening habitat networks in places where species may be highly fragmented. The populations of one of our iconic local species, the Scottish primrose, is becoming quite fragmented, particularly in Caithness, ironically because of changes in agricultural practices leading to lower grazing levels. We don’t know how climate change will affect this colourful plant, but given its limited northern coastal range, it really has few places to move to if conditions for it become unfavourable here.
After our dreich summer, the prediction that in Inverness the summer rainfall will decrease by 10-13 per cent by the 2050s may seem not too bad a prospect. However, it’s not that simple and the negative consequences of climate change for everyone are going to be profound and far-reaching.
So if you are interested in learning more about the climate change projections for Scottish cities, including Inverness, please have a look at the article Implications of Climate Change in Scotland at www.greenspacescotland.org.uk/1climate-change.aspx
Our commitment to helping Scotland address climate issues is detailed in Climate Change and Nature in Scotland – a summary of action for tackling climate change on www.snh.gov.uk.