the impacts on biodiversity Climate Change and the impacts on biodiversity

What is climate change ? Climate change refers to a statistically significant variation in either the mean state of the climate or in its variability, persisting for an extended period (typically decades or longer). Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average.

Biodiversity Biological diversity - or biodiversity - is a term we use to describe the variety of life on Earth. It refers to the wide variety of ecosystems and living organisms: animals, plants, their habitats and their genes. Biodiversity is the foundation of life on Earth. It is crucial for the functioning of ecosystems which provide us with products and services without which we couldn’t live. Oxygen, food, fresh water, fertile soil, medicines, shelter, protection from storms and floods, stable climate and recreation - all have their source in nature and healthy ecosystems. But biodiversity gives us much more than this. We depend on it for our security and health; it strongly affects our social relations and gives us freedom and choice.

Greenhouse effect : One of the major causes of climate change The earth receives energy from the sun, which warms the earth’s surface. As this energy passes through the atmosphere, a certain percentage (about 30) gets scattered. Some part of this energy is reflected back into the atmosphere from the land and ocean surface. The rest (70%) actually remains behind to heat the earth. In order to establish a balance, therefore, the earth must radiate some energy back into the atmosphere.

However, certain gases in the atmosphere form a sort of blanket around the earth and absorb some of this energy emitted back into the atmosphere. Without this blanket effect, the earth would be around 30 ° C colder than it normally is. These gases like carbon dioxide, methane, and nitrous oxide, along with water vapour, comprise less than one per cent of the atmosphere. They are called 'greenhouse gases' as the working principle is same as that which occurs in a greenhouse. 

Global Warming Carbon dioxide and other gases warm the surface of the planet naturally by trapping solar heat in the atmosphere. This is a good thing because it keeps our planet habitable. However, by burning fossil fuels such as coal, gas and oil and clearing forests we have dramatically increased the amount of carbon dioxide in the Earth's atmosphere and temperatures are rising.

We're already seeing changes. Glaciers are melting. plants and animals are being forced from their habitats. the number of severe storms and droughts is increasing

How is climate change creates an impact on biodiversity? Climate change has already produced significant and measurable impacts on almost all ecosystems, taxa and ecological processes, including changes in species distribution, timing of biological behaviours, assemblage composition, ecological interactions and community dynamics. Species have evolved over millions of years to adapt to specific climatic conditions as well as to variations in climate, but the current increase in temperature and differing weather patterns has occurred over an extremely short period of time which evolutionary processes are not able to match. Therefore, many species of plants and animals are not able to adapt to changing temperature and weather

Shifts in distribution of plants and animals At the simplest level, changing patterns of climate will alter the natural distribution limits for species or communities. In the absence of barriers it may be possible for species or communities to migrate in response to changing conditions. Vegetation zones may move towards higher latitudes or higher altitudes following shifts in average temperatures. Movements will be more pronounced at higher latitudes where temperatures are expected to rise more than nearer the equator. 

Changing patterns of precipitation and evaporation It is widely expected that rainfall variability and dry season severity will increase. Extreme flooding will have implications for large areas, especially riverside and valley ecosystems. Increasing drought and desertification may occur in tropical and sub-tropical zones, and at least one model has predicted a drying out of large parts of the Amazon.

Forests Tropical montane forests Higher temperatures will cause tropical montane forests to lose humidity. This drying out may cause invasion or replacement of montane forest species by lower montane or non-montane species.

II Boreal forests Increased temperatures may cause more frequent forest fires and create conditions favourable to pests; both will lead to degradation and loss of biodiversity. Boreal forests will shift towards Arctic areas.  Polar regions Permafrost is thawing which leads to additional release of soil carbon as CO2 , creating a positive feedback loop.

Marine Ecosystems The coastal margins. On coastal margins, especially where these are backed by areas of intense human use, rising sea levels may lead to the reduction of important coastal habitats such as mud flats and salt marshes.

Warmer oceans. Rising sea temperatures will further affect the distribution and survival of particular marine resources. Corals are extremely sensitive to minor increases in temperature which cause coral bleaching leading to loss of coral reef structure and impact negatively on the coral reef ecosystem. Increased acidification The ocean is becoming more acidic as it absorbs atmospheric CO2. This may result in organisms such as corals, plankton, shellfish and molluscs becoming less able to produce calcareous parts such as shells

Vrushti Gada Shweta Rajashekhar Std.: IX D.A.V. International School , Mulund