Global Warming in 2026: Causes, Evidence & Impacts

Global warming is the long-term rise in Earth’s average surface temperature caused mainly by human activities that increase heat-trapping greenhouse gases in the atmosphere. It is one part of the broader phenomenon of climate change, which also includes changes in rainfall, ocean heat, sea level, glaciers, extreme heat, drought, heavy precipitation, and other parts of the climate system.

The scientific evidence is extensive. NASA states that Earth is warming at an unprecedented rate and that human activity is the principal cause. The World Meteorological Organization’s 2026 State of the Global Climate 2025 report found that 2015–2025 were the hottest 11 years on record and that 2025 was the second- or third-warmest year measured, at about 1.43°C above the 1850–1900 average.

This article explains what global warming is, why greenhouse gases matter, how scientists know current warming is primarily human-caused, what changes are already being observed, why 1.5°C matters, and how mitigation and adaptation fit together.

Global Warming vs. Climate Change

Global warming refers specifically to the long-term increase in Earth’s average temperature.

Climate change is broader. It includes warming as well as related changes in:

Rainfall patterns.
Sea level.
Glaciers and ice sheets.
Ocean heat.
Extreme weather.
Ecosystems.

The terms are related but not identical.

What Causes Global Warming?

The main cause of current global warming is the human-driven increase in greenhouse gases.

Major sources include:

Burning coal, oil, and natural gas.
Deforestation.
Agriculture.
Industrial processes.
Waste and land-use change.

The Greenhouse Effect

The greenhouse effect is a natural process that keeps Earth warm enough for life.

Sunlight reaches Earth. The surface absorbs energy and later emits heat as infrared radiation. Greenhouse gases absorb and re-emit some of that heat, slowing its escape to space.

The problem is not that the greenhouse effect exists. The problem is that human activity has strengthened it by adding more greenhouse gases to the atmosphere.

Important Greenhouse Gases

Key greenhouse gases include:

Carbon dioxide.
Methane.
Nitrous oxide.
Fluorinated gases.
Water vapor, which mainly acts as a feedback rather than the primary driver of current warming.

Why Carbon Dioxide Matters

Carbon dioxide is released when fossil fuels are burned and when forests are cleared.

It remains in the climate system long enough that cumulative emissions matter. This means warming is closely related to the total amount of carbon dioxide humanity releases over time.

Methane

Methane is more powerful than carbon dioxide molecule for molecule over shorter timescales, but it remains in the atmosphere for less time.

Sources include:

Oil and gas systems.
Coal mining.
Livestock.
Rice production.
Landfills.

Reducing methane can help slow near-term warming.

How Do Scientists Know Warming Is Real?

Climate evidence comes from many independent sources.

NASA identifies observations including:

Rising global temperatures.
Warming oceans.
Shrinking ice sheets.
Retreating glaciers.
Declining snow cover.
Sea-level rise.
Changes in extreme events.

Scientists also use satellites, ocean buoys, weather stations, ice cores, tree rings, sediments, and other records.

How Do Scientists Know Humans Are the Main Cause?

Scientists compare observed climate patterns with the expected effects of different possible causes.

Several lines of evidence point to greenhouse gases rather than natural factors alone.

For example:

Greenhouse gas concentrations have risen sharply since industrialization.
The lower atmosphere and surface are warming while parts of the upper atmosphere cool.
Solar output does not show a long-term increase capable of explaining recent warming.
Climate models reproduce observed warming when human influences are included.

NASA notes that current warming cannot be explained by changes in the Sun.

Is Climate Change Natural?

Earth’s climate has always changed.

Past climate changes were caused by factors such as:

Orbital cycles.
Volcanic activity.
Solar variation.
Plate tectonics.

What makes current warming different is its speed and cause. The IPCC concludes that human influence on the climate system is unequivocal.

How Warm Was 2025?

WMO reports that 2025 was one of the three warmest years in the instrumental record.

The estimated global mean temperature was about 1.43°C above the 1850–1900 average.

The report also found that 2015–2025 were the 11 warmest years on record.

Does One Year Above 1.5°C Mean the Paris Goal Has Failed?

No.

The Paris Agreement’s temperature thresholds refer to long-term average warming, not a single year.

Individual years can temporarily exceed 1.5°C because of natural variability layered on top of human-driven warming.

However, repeated years near or above the threshold show how close the long-term climate is getting to that level.

Ocean Warming

The ocean absorbs most of the excess heat trapped by greenhouse gases.

WMO reports that ocean heat content reached the highest level in the observational record in 2025.

Ocean warming contributes to:

Sea-level rise.
Marine heatwaves.
Coral bleaching.
Changes in marine ecosystems.
More energy available for some extreme weather systems.

Sea-Level Rise

Sea level rises mainly because:

Warmer seawater expands.
Glaciers and ice sheets lose mass.

Sea-level rise increases the risk of coastal flooding, erosion, saltwater intrusion, and damage during storm surges.

Glaciers and Ice Sheets

Many glaciers around the world are retreating.

Greenland and Antarctica are also losing ice mass.

These changes affect sea level and can alter freshwater availability in regions that depend on seasonal snow and glacier melt.

Extreme Heat

As average temperatures rise, extreme heat becomes more likely and more intense in many regions.

Heatwaves can affect:

Human health.
Electricity demand.
Agriculture.
Outdoor work.
Infrastructure.

Heavy Rainfall

A warmer atmosphere can hold more water vapor.

This can increase the intensity of heavy rainfall in many regions, although local precipitation trends vary.

Drought

Climate change can worsen drought risk in some areas through higher temperatures, altered rainfall, and increased evaporation.

Drought affects water supplies, agriculture, ecosystems, and wildfire risk.

Wildfire

Climate change is not the only cause of wildfire.

Land management, ignition sources, vegetation, and weather all matter.

However, hotter and drier conditions can increase fire weather and make some landscapes more vulnerable.

Tropical Cyclones

Climate change does not mean every cyclone is directly “caused” by warming.

However, warmer oceans and higher sea levels can affect cyclone intensity, rainfall, and storm-surge impacts.

Climate Change and Food

Agriculture depends heavily on climate.

Potential risks include:

Heat stress.
Drought.
Flooding.
Pests.
Crop disease.
Changing growing seasons.

Technology and adaptation can reduce some risks, but not all impacts can be eliminated.

Climate Change and Health

Health effects can include:

Heat illness.
Worsened air quality.
Changing ranges of some disease vectors.
Food and water insecurity.
Mental-health effects after disasters.

Climate Change and Inequality

Climate risks are not distributed equally.

Low-income communities may have fewer resources for cooling, insurance, relocation, resilient housing, or disaster recovery.

Countries that contributed relatively little to historical emissions can still face severe climate impacts.

Mitigation

Mitigation means reducing the causes of climate change.

Examples include:

Replacing fossil fuels with low-carbon energy.
Improving energy efficiency.
Reducing methane emissions.
Electrifying transport and heating where practical.
Protecting and restoring ecosystems.
Reducing industrial emissions.

Adaptation

Adaptation means preparing for climate impacts that are already occurring or cannot be completely avoided.

Examples include:

Heat-action plans.
Flood defenses.
Drought-resistant crops.
Water conservation.
Early-warning systems.
Resilient infrastructure.

Why We Need Both Mitigation and Adaptation

Adaptation alone cannot prevent unlimited warming.

Mitigation alone cannot erase impacts that are already occurring.

The IPCC emphasizes that both are needed to reduce climate risk.

Renewable Energy

Solar and wind power have expanded rapidly and can reduce electricity-sector emissions when they displace fossil-fuel generation.

Electricity systems also need:

Transmission.
Storage.
Flexible demand.
Reliable balancing resources.

Nuclear Energy

Nuclear power produces low direct carbon emissions during operation and can contribute to low-carbon electricity systems.

It also involves trade-offs involving cost, construction time, waste management, safety, and public acceptance.

Carbon Capture

Carbon capture and storage may help reduce emissions from some industrial processes and fossil-fuel facilities.

It is not a substitute for all other mitigation because capture rates, cost, infrastructure, and energy requirements matter.

Individual Actions

Individual choices can reduce emissions, especially when combined with supportive infrastructure and policy.

Examples include:

Using efficient appliances.
Driving less where alternatives exist.
Reducing food waste.
Improving home insulation.
Choosing lower-carbon electricity where available.

However, climate change cannot be solved only through consumer behavior. Energy systems, transportation, buildings, agriculture, and industry also require structural change.

Common Climate Myths

Myth: The climate has changed before, so humans cannot be causing current warming.
Reality: Past natural climate change does not rule out a different cause today.

Myth: Cold weather disproves global warming.
Reality: Weather is local and short-term; climate describes long-term patterns.

Myth: The Sun is causing current warming.
Reality: Solar trends do not match the observed warming pattern.

Myth: Scientists only use computer models.
Reality: Climate science relies on observations, physical theory, paleoclimate data, satellites, instruments, and models.

What Can Still Be Prevented?

Every additional fraction of a degree matters.

Future warming depends strongly on future emissions.

Reducing emissions cannot return the climate instantly to its earlier state, but it can reduce the amount of additional warming and therefore reduce future risks.

Frequently Asked Questions

Is global warming real?

Yes. Multiple independent observations show long-term warming of the atmosphere and oceans.

Are humans causing global warming?

Yes. The IPCC and NASA conclude that human activities, primarily greenhouse gas emissions, are the main cause of recent warming.

Was 2025 the hottest year ever?

WMO ranked 2025 as the second- or third-warmest year depending on dataset, at roughly 1.43°C above the 1850–1900 average.

Can global warming be stopped?

Warming can be limited by reducing net greenhouse gas emissions. Some changes are already unavoidable, which is why adaptation is also necessary.

Why Climate Risk Depends on Exposure and Vulnerability

A climate hazard does not produce the same outcome everywhere. The effect of a heatwave, flood, drought, or storm depends on who and what is exposed and how vulnerable those people and systems are. The same temperature can be much more dangerous in a neighborhood with little shade, unreliable electricity, poor housing, and limited healthcare than in a community with cooling centers and resilient infrastructure.

This is why climate adaptation includes social and economic planning as well as engineering. Early-warning systems, public-health preparedness, building standards, insurance, emergency communication, water management, and urban design can all reduce losses even when the physical hazard cannot be eliminated.

Climate Solutions Need to Be Evaluated as Systems

No single technology can solve climate change by itself. Solar power needs grids and storage or other balancing resources. Electric vehicles require electricity supply and charging infrastructure. Building efficiency depends on construction quality and financing. Forest restoration must account for land rights, ecosystems, and long-term management.

Effective climate policy therefore combines technologies, institutions, investment, and behavior. The best mix differs by country because energy resources, income, infrastructure, geography, and development needs differ. What remains common is the need to reduce net greenhouse gas emissions while making communities more resilient to unavoidable impacts.

Why Delayed Action Raises Future Costs

Climate infrastructure turns over slowly. Power plants, buildings, roads, factories, and vehicle fleets can remain in service for decades, so decisions made today influence emissions and vulnerability far into the future. Delaying cost-effective changes can lock in higher emissions and require faster, more disruptive adjustments later.

Early planning also gives communities more time to upgrade drainage, cooling, water systems, and emergency preparedness before hazards become more severe.

Conclusion

Global warming is not a distant prediction. It is a measured change in Earth’s climate system that is already affecting temperatures, oceans, ice, sea level, and extreme weather risks.

The strongest evidence points to human greenhouse gas emissions as the principal cause of current warming. Natural variability still affects individual years and regions, but it does not explain the long-term global trend.

The WMO’s 2026 assessment shows how far the climate has already changed: the last 11 years were the warmest 11 on record, ocean heat content reached a record high, and 2025 was roughly 1.43°C warmer than the preindustrial baseline.

The practical response is not to choose between mitigation and adaptation. Both are needed. Reducing emissions limits future warming, while adaptation reduces damage from changes that are already happening.