Imagine if you could no longer find your favourite bird on the wetland in winter, or if trees were dying in your local wood for lack of water in summer. What if the fish in our rivers changed, and salmon became scarce while other species flourished?
These scenarios are looking more likely. The variety of life in our ecosystems and habitats (biodiversity) is already changing and whilst some species will prosper, many will suffer. Climate change causes all of nature to change too and some plants and animals may have difficulty coping.
A group of experts has come together to produce a Report Card of climate change impacts on plants and animals in the UK – effects that we’re already seeing and changes that might happen in future. Since the last Report Card in 2013, scientists have become more certain about some of the effects, and have found out that other changes might also be happening.
Climate controls many of nature’s important functions, like plant growth, nutrient cycles in soil and water, and triggers for plants to flower and animals to breed. As the climate changes these vital functions could be affected.
Plants and animals are on the move. A ‘range-shift’ is when the area in which a species can usually be found changes.
We have expected range-shifts to the north. As the earth warms, northern regions will have milder temperatures, so southern species may be able to survive further north and become more common there. Equally, southern regions might become too hot for some species which could disappear as they move northwards in search of cooler climates.
Between 1960 and 2000 many species groups moved. Mammals, butterflies, fish, and ground beetles have moved north, but not quite as much as scientists had predicted. Damselflies, dragonflies, spiders and woodlice on the other hand have journeyed further north than expected (see figure below).
So, climate change shifts the balance within nature.
Birds, for instance, have moved north by an average of 37km between 1990 and 2008. Some birds might thrive in warmer temperatures and their populations could increase, but others, like some wetland birds, may be pushed to spend winters elsewhere.
Some small birds might not survive more rain in the winter. Although we could have the same amount of rain during the year, climate change may mean that rainfall patterns are different. For example, there might be longer dry spells but then lots of heavy rain at one time and some birds, such as capercaillie and black grouse, may have a harder time breeding.
The updated climate change Report Card has lots of information on these changes and more. It shows that many changes are expected in the future, but also that a great deal has already happened.
We need to be concerned. Of course nature is worth preserving in itself, but our basic needs are met by nature’s benefits; our economy, for example, relies on its services. The effects of climate change on nature will affect us all.
Parasites that thrive in warmer, wetter weather could become more common, and lead to declines in bird populations. For red grouse, a type of nematode (parasitic worm) could lead to a drop in fertility and a population decline. This could be made worse by heather beetle on heather, which may affect grouse shooting in Scotland, an activity worth £23m a year to the Scottish economy.
Similarly, angling for salmon and trout in Scotland is worth around £90m each year. Cold-water fish like salmon and trout are likely to be threatened by increasing temperatures in freshwaters, while warmer-water fish such as carp may flourish.
In freshwaters, an overload of nutrients spill into the water from fertilisers, industries and other sources of pollution causing algae to bloom. The thick, soupy algae form a layer on the surface of the water. This blocks sunlight from reaching the other plants in the water and sucks up all of the oxygen, leaving little for other creatures, and it can sometimes also be poisonous to humans and pets. Higher temperatures from climate change and nitrogen deposition from exhaust fumes and industrial emissions could make this worse. It may also affect fish communities and water supply, both of which play an important role in our lives.
But there are things we can do to help.
You can reverse the effects of pollution. At Loch Leven, a cleaner loch is the result of many years of people coming together and working to reduce pollution in the water. Monitoring has shown that the loch is now more resilient to warmer summers. You can read more about how work at Loch Leven is helping nature adapt in this case study.
The Report Card ends on a positive note: there are ways that we can help nature to adapt. We need to limit climate change by controlling greenhouse gas emissions like carbon dioxide from our cars and power stations, and to help nature to be more resilient. You can see examples of the work we are carrying out to help nature adapt to climate change in these other case studies.
The Biodiversity Climate Change Impacts Report Card is a handy document, with plenty of examples of environmental change, and you can see it here.