Effects of global climate change

Global climate change can affect both the physical environment and living things. As the planet warms, the effects differ between regions: one area may become drier while another experiences heavier rainfall.

Effects on the physical environment

Sea levels can rise as warming seawater expands and melting ice on land adds water to the oceans. Rising seas can increase coastal flooding and cause the loss of low-lying land.

Rainfall patterns can change because warming affects evaporation and the movement of air and moisture. Some regions may receive less rainfall or experience longer dry periods, while others may receive more rain or heavier downpours.

Extreme weather can become more frequent or more severe. For example, higher temperatures can increase the likelihood of heatwaves, while heavier rainfall can increase flooding. The effects depend on the region and the type of extreme weather.

Effects on habitats and species

A habitat provides the conditions a species needs to live. Changes in temperature, rainfall and sea level can alter or destroy habitats. For example, prolonged drying can make an area less suitable for species that need wet conditions.

As conditions change, some species may move to areas with more suitable conditions, changing their distribution. Others may be unable to move or adapt quickly enough, so their populations may decline.

Climate change risks and implications

Climate change affects the natural environment across the globe, but its effects are not the same everywhere. Changes in temperature, rainfall and sea level can vary in size and timing between places. A change that appears small when averaged across the world can still have serious local consequences.

Judging climate change risks

A risk depends on both the likelihood of a harmful change and the seriousness of its consequences. A likely change that causes limited damage may be a concern; a less likely change can also be a major risk if the damage would be severe. Judging climate change therefore involves considering both how large a change may be and what could be affected by it.

The same change can create different levels of risk in different places. For example, rising sea level can flood or erode low-lying coastlines, damaging coastal habitats. The extent of the damage depends partly on how exposed a particular coastline is and how much the sea level rises there.

Environmental implications of climate change

Changes in temperature and rainfall can alter habitats: the places where organisms live. Some organisms may be unable to survive in the changed conditions or move to a suitable habitat. This can disrupt ecosystems and reduce biodiversity, the variety of living organisms.

Changes in rainfall can also affect water availability. Less reliable rainfall or more prolonged dry conditions can reduce the freshwater available to organisms and damage ecosystems that depend on it. These effects can interact: a reduction in water availability, for example, can change a habitat and threaten the species living there.

Global warming and climate change

Global warming is a sustained rise in the Earth’s average temperature. It is a major cause of climate change: long-term changes in climate patterns, including temperature, rainfall, winds and the frequency of extreme weather.

As the Earth warms, the atmosphere, oceans, ice and land change. For example, warming can melt ice and alter evaporation from the oceans. These changes, together with changes in air movement, can shift rainfall and wind patterns over time. The frequency of some types of extreme weather can also change.

Climate change is not the same as a single warm day or season. Weather varies from day to day, but climate describes patterns over a long period. A rise in the global average temperature does not mean that every place warms by the same amount or that every day is warmer than before.