Effects of climate change

Climate change is affecting Earth in many ways, both in nature and for people. We see more extreme weather, such as stronger heat waves, heavier rains, and bigger storms. Wildfires grow larger because of heat and dryness, while coral reefs lose their colour and health from warmer and more acidic oceans. These changes can harm animals and plants, force some to move to cooler places, and damage places where people live and work.

The Arctic is warming faster than other areas, and ice sheets and oceans are taking in much of the extra heat, which can cause sea levels to rise over time. This rising water threatens 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. Understanding 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 warming up. Global temperatures have gone up by about 1.1 °C (2.0 °F), and scientists expect them to keep rising. Land areas, especially the Arctic, are warming faster than the oceans. Night-time temperatures are increasing more quickly than daytime temperatures. How much hotter it gets depends on how much we pollute the air with gases that trap heat.

Scientists study old clues like tree rings, ice cores, corals, and mud from lakes and oceans to learn about past climates. They found 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. Back then, the Earth was much warmer, and the sea level was tens of meters higher than today. Even if we stopped polluting right now, the Earth would stay warm for many centuries.

Weather

Large increases in the frequency and intensity of extreme weather events are expected as the planet warms. Extreme heat events are expected to be among the most affected by global warming.

Climate Central’s review of climate attribution studies found that climate change made almost all studied event types substantially more likely or more severe.

The lower and middle atmosphere are heating due to the greenhouse effect. This causes more water to evaporate, and the extra water vapour in the air makes storms stronger. This leads to heavier rain and snow, and increases the risk of flooding. Drier conditions become drier, increasing the risk of heat waves and wildfires. Scientists can now measure how much climate change has made specific extreme weather events worse.

Heat waves and temperature extremes have become more common and stronger almost everywhere since the 1950s due to climate change. There are fewer very cold days and more very hot days.

Warming leads to more overall precipitation. Rain and snow can fall more heavily, especially during wet seasons, while dry seasons become drier. In some areas, like the northern high latitudes, there is more snow and rain. In other areas, like parts of the Southern Hemisphere, rain patterns have shifted.

Storms, including tropical cyclones and extratropical cyclones, are expected to become wetter and sometimes stronger. While there may be fewer tropical cyclones overall, the ones that do occur could be more powerful. This change in storm patterns affects regions around the world.

Land

Climate change is changing 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 actually 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. This creates a cycle where fires release more greenhouse gases, which then leads to even more warming. Some areas have seen more fires directly linked to climate change.

Changes in weather patterns can also 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 massive 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, making the sea level rise. This change affects coastal areas and can lead to flooding in places where people live and work. Warmer temperatures also change how salt is spread in the ocean, which can 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 about 8% of their size between 1971 and 2019. In places like the Andes and the Himalayas, melting glaciers might affect water supplies and could cause dangerous floods.

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. This change would last for many years and could not be undone.

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. By the middle of this century, some Arctic summers might have no sea ice at all.

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).

Recent warming has greatly affected natural systems. Animals and plants around the world are moving to cooler places, such as higher altitudes on land or deeper waters in the ocean. Climate change has been one of the biggest influences on nature over the past fifty years, affecting areas 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 overuse of resources, threatening to harm or even destroy some unique habitats and species. This can change how entire ecosystems work, affecting rainfall, plant growth, animal movements, and ocean life. These changes can also impact humans by affecting food supplies, water sources, and natural defenses against storms.

Ecosystems on land

Climate change is a major reason why many plants and animals are struggling to survive in different types of land areas, such as forests, grasslands, and tundra. While other factors like land clearing can also cause harm, climate change is expected to become the main cause of loss of plant and animal variety in the future. Even today, some areas face serious risks, with many species becoming endangered. For example, insects and salamanders are especially vulnerable.

Rainfall in the Amazon rainforest helps keep the forest alive by evaporating back into the air. However, deforestation and more frequent droughts caused by climate change are putting this balance at risk. Scientists worry that the rainforest might change into a drier landscape 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 waters in the ocean are causing more frequent events that harm sea life, such as times when the water gets too hot for many creatures to survive and when colorful sea plants lose their color. Some harmful plants in the water are also increasing because of warmer, less oxygen-rich waters. Melting ice also removes homes for some sea plants.

Oceans are also becoming more acidic, which can hurt animals that build shells, like certain 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 support many sea creatures and help protect coastlines, but many could disappear even if warming is limited. Other important sea habitats, 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, called tipping points. These 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. There is a risk that some of these tipping points may already be happening, such as changes in ice sheets and coral reefs.

These tipping points can be very dangerous because they might cause lasting damage. For example, changes in ocean currents could affect weather and temperatures far away. Some tipping points are connected, so one change might cause others to happen. These changes could affect nature and human societies for many years, possibly leading to the loss of some plants, animals, and even cultures.

Health, food security and water security

Humans do best in a certain temperature range, and when temperatures go outside this range, 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 certain areas more than others, especially the Arctic, Africa, small islands, parts of Asia, and the Middle East. Places that are less developed and closer to the equator are often at higher risk.

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

Hot weather can be a big problem for cities. Many areas could become as hot as the Sahara Desert in the next 50 years if we keep adding greenhouse gases to the air. This heat can be dangerous because it goes beyond what people are used to. Cities lose shade from trees when it gets too hot, making the problem even 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 even be completely covered by water, forcing people to move away.

Impacts on societies

Climate change affects many parts of our lives. It can change our health, make clean water and food harder to find, and affect how rich or poor we are. These changes can make problems worse 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 anymore. Moving can be hard, especially for families who have to leave their homes behind.

Climate change can also cause arguments and problems between groups of people, especially when there isn’t enough food or water to go around. It can make it harder for governments to help everyone, and sometimes people might join groups that cause trouble because they have few other choices.

Some groups, like children, older people, and those who are less wealthy, feel the effects of climate change more strongly. For example, children are more likely to get sick from pollution and hot weather. People in poor areas often have fewer resources to deal with changes in the weather, making their lives even harder.

Economic impacts

Main article: Economic analysis of climate change

The effects of climate change on the world's economy can vary a lot. If we don't make changes to adapt, the impacts could be worse. Scientists use special ways to guess how much money these changes might cost, but these guesses might not fully show how bad things could get.

The more the Earth warms up, the bigger the economic problems become. Studies show that if the temperature rises by just 1.5°C, the damage is much 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 has also made 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.