Effects of climate change

Climate change is changing Earth in many ways. We see more extreme weather, like stronger heat waves, heavier rains, and bigger storms. Wildfires can grow larger because of heat and dryness. Coral reefs can lose their colour and health from warmer and more acidic oceans. These changes can harm animals and plants, and sometimes force them to move to cooler places. They can also damage places where people live and work.

The Arctic is warming faster than other places. Ice sheets and oceans take in much of the extra heat, which can cause sea levels to rise over time. This rising water can threaten coastal cities, wetlands, and island nations. People everywhere feel the effects, with changes to food and water supplies, health risks, and economic challenges. Children, poor communities, and indigenous peoples are often among those most affected. Learning about these effects helps us find ways to protect our planet and each other.

Changes in temperature

Further information: Global surface temperature, Instrumental temperature record, and Heat wave

The Earth's climate is getting warmer. Global temperatures have risen by about 1.1 °C (2.0 °F), and scientists think they will keep going up. Land areas, especially the Arctic, are warming faster than the oceans. Night-time temperatures are rising quicker than daytime temperatures. How much hotter it gets depends on how much we pollute the air with heat-trapping gases.

Scientists look at old clues like tree rings, ice cores, corals, and mud from lakes and oceans to learn about past climates. They discovered that today’s temperatures are higher than they have been in the last 2,000 years. If we keep polluting, temperatures could reach levels not seen for about 3 million years. At that time, the Earth was much warmer, and the sea level was much higher than today. Even if we stopped polluting now, the Earth would stay warm for many centuries.

Weather

As the planet warms, we see more extreme weather events like heat waves and heavy rains. Climate change makes these events more likely and often worse.

The air is heating up because of the greenhouse effect. This means more water evaporates, and the extra water vapour makes storms stronger. This can lead to heavier rain and snow, and a higher risk of flooding. Dry places can become even drier, which increases the risk of heat waves and wildfires.

Since the 1950s, heat waves and very hot days have become more common because of climate change. There are fewer very cold days now.

Warming also changes how much and where rain and snow fall. Some places, like the northern high latitudes, get more snow and rain. In other areas, rain patterns have changed.

Storms, including tropical cyclones and extratropical cyclones, may become wetter and sometimes stronger. Even though there might be fewer tropical cyclones, the ones that happen could be more powerful. These changes affect many parts of the world.

Land

Climate change changes how land behaves in many ways. It can make soil drier, which affects plants and farming. In some places, like California, very dry conditions have led to serious droughts.

Heavy rains can cause floods, but in some areas, drier soil might reduce flooding because it soaks up water faster. However, if the soil becomes too hard, heavy rain can run off quickly into rivers, increasing flood risks.

Wildfires have become more common and intense because hotter, drier weather makes forests and plants easier to catch fire. Some areas have seen more fires linked to climate change.

Changes in weather patterns can affect earthquakes and volcanoes. For example, melting ice and changes in water weight on the Earth's surface can trigger earthquakes. In Greenland, melting glaciers caused a big collapse that created a large wave, showing how climate change can have surprising effects on the land.

Oceans

Sea level rise

The Earth's oceans are changing because of climate change. As the planet warms, ice from glaciers and ice sheets melts into the water. This makes the sea level rise. This change can affect coastal areas and may cause flooding where people live and work. Warmer temperatures can also change how salt moves in the ocean, which may impact sea creatures and weather patterns.

Ice and snow

Earth lost 28 trillion tonnes of ice between 1994 and 2017, with melting grounded ice (ice sheets and glaciers) raising the global sea level by 34.6 ±3.1 mm. The rate of ice loss has risen by 57% since the 1990s−from 0.8 to 1.2 trillion tonnes per year.

The cryosphere, the part of Earth covered by snow or ice, changes a lot with the climate. Since 1981, there has been a big drop in snow on land, especially in the spring. In the future, snow cover is expected to keep shrinking almost everywhere.

Glaciers decline

Further information: Retreat of glaciers since 1850

Since the early 1900s, many glaciers around the world have been getting smaller. Glaciers not connected to big polar ice sheets lost some of their size between 1971 and 2019. In places like the Andes and the Himalayas, melting glaciers might affect water supplies.

Ice sheets decline

Further information: Antarctic ice sheet § Changes due to climate change, and Greenland ice sheet § Recent melting

The melting of the Greenland and West Antarctic ice sheets will keep adding to rising sea levels for a very long time. Greenland’s ice is mostly melting from the top, while Antarctic ice is melting because warm ocean water is reaching it. If the West Antarctic ice sheet melts a lot, it could cause sea levels to rise very quickly.

Sea ice decline

Reporting the reduction in Antarctic sea ice extent in mid 2023, researchers concluded that a "regime shift" may be taking place "in which previously important relationships no longer dominate sea ice variability".

Further information: Arctic sea ice decline and Antarctic sea ice § Recent trends and climate change

Sea ice helps keep Earth cool by reflecting sunlight back into space. As the planet warms, there is less snow and sea ice. When sea ice melts, the ocean absorbs more heat, which makes the warming even stronger. In the Arctic, sea ice has been melting faster each year.

Permafrost thawing

Further information: Permafrost § Impacts of climate change, and Climate change in Russia § Permafrost

Permafrost, which is soil that stays frozen for many years, has been warming up. This makes the ground weak and can damage buildings and roads. When permafrost thaws, it can also release gases that make the Earth even warmer.

Wildlife and nature

Part of the Great Barrier Reef in Australia in 2016 after a coral bleaching event (partly caused by rising ocean temperatures and marine heatwaves).

The world is getting warmer, and this is changing nature. Animals and plants are moving to cooler places, like higher up on land or deeper in the ocean. Climate change has been one of the biggest changes to nature in the last fifty years. It affects many places and creatures in many ways.

As climate change continues, its effects on nature will likely grow. These changes combine with other problems like land clearing, pollution, and using too many resources. This can threaten some special homes for animals and plants and even destroy them. These changes can also affect people by changing food, water, and protection from storms.

Ecosystems on land

Climate change is making it hard for many plants and animals to live in places like forests, grasslands, and tundra. While other things like cutting down trees can also cause harm, climate change is expected to become the biggest reason why plants and animals are in danger in the future. Even today, some places are at serious risk, and many animals are in danger. For example, insects and salamanders are especially at risk.

Rainfall in the Amazon rainforest helps keep the forest alive. But cutting down trees and more frequent droughts from climate change are putting this at risk. Scientists worry the rainforest might become drier over time if these problems continue.

Marine ecosystems

Climate change will affect coral reef ecosystems, through sea level rise, changes to the frequency and intensity of tropical storms, and altered ocean circulation patterns. When combined, all of these impacts dramatically alter ecosystem function, as well as the goods and services coral reef ecosystems provide.

Warmer ocean water is causing more events that harm sea life, like times when the water gets too hot for many sea creatures. Some colorful sea plants are also losing their color because of warmer water. Some harmful plants in the water are also growing more because of warmer, less oxygen-rich water. Melting ice is also taking away homes for some sea plants.

Oceans are also becoming more acidic, which can hurt animals that build shells, like some sea creatures. Some tiny plants in the water may grow more, but some of these can be dangerous to fish. Reducing pollution can help lessen these effects.

Warm-water areas where many colorful sea animals live are especially sensitive to warming and changes in the ocean. These areas help protect coastlines, but many could disappear even if warming is limited. Other important sea homes, like mangroves and seagrass areas, are also at risk from higher temperatures.

Tipping points and irreversible impacts

Main articles: Tipping points in the climate system and Abrupt climate change

There is a number of places around the globe which can pass a tipping point around a certain level of warming and eventually transition to a different state.

The climate system can reach points where big changes happen quickly. These are called tipping points. They can cause parts of nature, like ice sheets or forests, to change in ways that are hard to reverse. Scientists study these points using old data and computer models. Some of these changes might already be happening.

These tipping points can be dangerous because they might cause lasting damage. For example, changes in ocean currents could affect weather far away. Some tipping points are connected, so one change might cause others. These changes could affect nature and people for many years.

Health, food security and water security

Humans do best in a certain temperature range. When temperatures get too hot or too cold, it can be hard for people to stay healthy and have enough food and water. Right now, millions of people live in areas that are too warm for the best health and food conditions. As the Earth gets warmer, more people will find it harder to stay healthy and get enough food and water.

Projected changes in average food availability (represented as calorie consumption per capita), population at risk of hunger and disability-adjusted life years under two Shared Socioeconomic Pathways: the baseline, SSP2, and SSP3, scenario of high global rivalry and conflict. The red and the orange lines show projections for SSP3 assuming high and low intensity of future emissions and the associated climate change.

Climate change affects how much food we can grow. It changes the weather, makes droughts more common, and can hurt animals that give us milk and meat. It also makes soil worse and can turn land into desert. These changes make it harder to grow enough food for everyone. Warmer oceans and changes in the water also mean there is less fish to catch.

Climate change also affects our water. It can make water harder to find during dry times and can make water dirty when it rains a lot. In some places, rising sea levels can mix salt into the water we use. All of these changes make it harder to plan for clean, safe water for everyone.

Human settlements

Climate change affects some places more than others. Areas like the Arctic, Africa, small islands, parts of Asia, and the Middle East are at higher risk. Places closer to the equator and those that are less developed are also more affected.

Overlap between future population distribution and extreme heat in a high emission scenario

Hot weather can be a big problem for cities. Many places could become very hot like the Sahara Desert in the next 50 years if we keep adding greenhouse gases to the air. This heat can be dangerous because it is more than what people are used to. Cities lose shade from trees when it gets too hot, which makes the problem worse.

Coastal areas are also at risk. Rising sea levels can flood cities near the water. Stronger storms and salty water moving into underground water sources add to these dangers. Many people live near coasts, and some small islands could be covered by water, forcing people to move away.

Impacts on societies

Climate change changes many parts of our lives. It can affect our health, make clean water and food harder to find, and change how rich or poor we are. These changes can make life harder for people who are already struggling.

When the climate changes, some people may need to move to safer places. This can happen because of big storms or because places become too dry or too hot to live in. Moving can be hard, especially for families who have to leave their homes.

Climate change can also cause problems between groups of people, especially when there isn’t enough food or water. It can make it harder for governments to help everyone.

Economic impacts

Main article: Economic analysis of climate change

Climate change can affect the world's economy in many ways. If we don't change how we live, the problems could get worse. Scientists try to guess how much money these changes might cost, but it's hard to know exactly how bad things will get.

The more the Earth warms up, the bigger the economic problems become. If the temperature rises by 1.5°C, the damage is less than if it rises by almost 4°C. Some studies say that by the end of the century, the world's money made each year (GDP) could be smaller because of climate change. Extreme weather events, like big storms and floods, have also made costs go up since the 1970s.

Economic inequality

Climate change can make the world's rich and poor more different. Countries in colder areas may not feel much change, while hotter countries may grow more slowly.

Highly affected sectors

Some jobs and industries are hit harder by climate change than others. Farming, fishing, and cutting trees can lose money because of droughts and very hot weather. Tourism and work outside may also have limits if the world gets too warm.

Power plants that use water can have problems if there is less water or if it gets too hot. This can make them work less well. Power from rivers (hydropower) can also go down if there is less water. Climate change can also affect oil and gas buildings, making them more likely to be damaged by big storms or rising sea levels.

Insurance costs are going up because of climate change, especially for things like flood damage. This can make it hard for some families to afford insurance. Climate change may also affect shipping by changing how much water is in places like the Panama Canal, which can slow down how many ships can pass through.