The Fingerprint of Climate Change

Across the globe, climate change is making it hotter and wetter. Warmer temperatures are disrupting the usual balance of nature and posing risks to humans, animals and plants. They are affecting the habitats of animals and causing changes in their behavior, including migration patterns.

Climate change is caused primarily by human activities. The fossil fuels we burn produce carbon dioxide, which rises in the atmosphere and traps heat. Other greenhouse gases, such as methane and nitrous oxide, are also produced by human activity. These emissions, together with a range of other pollutants, are changing the Earth’s energy balance by altering the way it absorbs and radiates energy.

The physics of these gases alone would cause about 2 degrees Celsius of warming, but in practice there are many other effects (feedbacks) that amplify or diminish the initial warming. These include melting of polar sea ice, which exposes darker ocean and land surfaces to the sun; water vapour, which is also a potent greenhouse gas but has a short lifetime in the atmosphere so tends to be an amplifier rather than a driver of warming; changes in cloud cover; and other natural phenomena such as volcanic eruptions.

All of these factors are important, and many have had their own influences on Earth’s temperature in the past. But when scientists look at the overall pattern of global and regional atmospheric temperature changes, they find that the fingerprint is much closer to that induced by long-term increases in CO2 than it is to other influences.

These fingerprints are based on scientific observations of the Earth’s climate, and not predictions from models that try to explain observed changes. These observations are backed up by data from the global monitoring network of weather stations and ships, as well as from satellites and geologic records.

While the effects of climate change are happening all over the world, some regions are more vulnerable than others. For example, some regions are already experiencing the increased intensity of extreme events such as storms, heat waves and droughts.

These climate impacts are often exacerbated by social, economic and geographic factors. For instance, people living in poverty are more likely to die from climate-related incidents such as floods and disease outbreaks. They are also less able to adapt or mitigate against these impacts. In addition, higher temperatures and changes in rainfall and sea levels affect access to clean drinking water and food crops. This is especially true in highly vulnerable regions such as West, Central and Eastern Africa, South Asia, Central America, the Caribbean islands, and the Arctic. Lastly, changes in temperature and rainfall patterns may promote the spread of insect-borne diseases such as malaria and dengue fever. This is because warmer temperatures lead to higher populations of mosquitos, ticks and fleas that carry them. They can also promote the spread of bacterial diseases such as diarrhea and cholera. As the climate continues to warm, these threats will continue to grow.

Scroll to top