While there are many actions you can take to do your part in the fight against climate change, a great place to start is to educate yourself about the factors that contribute to our changing climate, and no factor plays a larger role than the concentration of greenhouse gases (GHGs) in our atmosphere.
You’ve likely heard that greenhouse gases play a role in global warming and that certain human activities release large quantities of these gases into the atmosphere, increasing global warming. Greenhouse gases, however, are not all bad and have played a role in regulating the global temperature throughout Earth’s history.
Today, we will cover the nature of greenhouse gases so you can understand the role they play in our global climate. We will also go over some of the implications caused by an excessive amount of greenhouse gases released through human activity.
Key takeaways
- Greenhouse gases keep Earth habitable. Without them the planet would average just under 0°F. The problem is rising concentrations from human activity.
- Carbon dioxide makes up about 74% of human caused emissions, methane about 17%, nitrous oxide about 6%, and fluorinated gases about 2%.
- Global emissions reached a record 55 billion tonnes of CO2 equivalent in 2025, and grew 51% from 1990 to 2021.
- Energy accounts for about 75.7% of emissions and agriculture about 11.7%. Power generation was the only sector whose emissions fell in 2025.
- China, the United States, and India emit the most today, while the United States, China, and Russia have emitted the most since 1850.
- The ocean and land absorb about half of human CO2 emissions. The rest stays in the air, leaving CO2 about 52% above preindustrial levels.
- Cutting emissions is the main lever. Carbon offsets fund verified reductions and removals elsewhere and work alongside cutting your own emissions.
Greenhouse Gases in 2026: The Latest Data
Here is where the numbers stand, based on the EU’s EDGAR database, the World Resources Institute, and the Global Carbon Budget 2025.
2026 greenhouse gas data snapshot
- Record emissions: Global greenhouse gas emissions reached a record 55 billion tonnes of CO2 equivalent in 2025, up 0.9% from 2024. Power generation was the only major sector to see emissions fall (down 0.3%), and it is still the largest at nearly 30% of the total.
- Long term growth: Global emissions grew 51% from 1990 to 2021, according to the World Resources Institute.
- Concentrations: Atmospheric CO2 is about 425 parts per million for 2025, roughly 52% above the preindustrial level of about 278 parts per million. The ocean and land absorbed about 29% and 21% of human CO2 emissions over the past decade, so about half stays in the air.
- Who emits most: In 2025, China accounted for 29.5% of global greenhouse gas emissions, the United States 11.1%, and India 8.3%. China’s emissions were essentially flat (up 0.1%) and India’s slipped 0.2%, the first time both held steady or fell, even as the global total hit a record.
What Are Greenhouse Gases?
Greenhouse gases are what cause the greenhouse effect within Earth’s atmosphere. These gases are responsible for retaining heat here on Earth. Without these gases, the temperature of our planet would drop from its average global temperature of 57°F to just under 0°F.
While greenhouse gases play a role in maintaining a habitable global temperature, human activity has increased these gases’ atmospheric concentration, causing too much heat to become trapped in our atmosphere. The extra heat in our atmosphere leads to increased temperatures around the globe and climate change.
Let’s go over the types of greenhouse gases and how they come about.
What Are the Types of Greenhouse Gases?
The air surrounding Earth primarily consists of the atmospheric gases nitrogen, oxygen, and argon. Everything else is a tiny fraction. Carbon dioxide, for example, makes up only about 0.04% of the atmosphere, roughly 425 parts per million in 2025. While this percentage may seem small, these gases play a significant part in the greenhouse effect responsible for regulating Earth’s temperature.
There are six main greenhouse gases:
- Water vapor
- Carbon dioxide
- Methane
- Nitrous oxide
- Ozone
- Synthetic greenhouse gases
Water vapor, carbon dioxide, methane, nitrous oxide, and ozone have natural and anthropogenic (human driven) causes.
Along with these naturally occurring greenhouse gases, a handful of synthetic gases have been emitted solely due to human activity. Most of these gases are called fluorinated gases and include:
- Perfluorocarbons (PFCs)
- Hydrofluorocarbons (HFCs)
- Chlorofluorocarbons (CFCs)
- Sulfur hexafluoride
- Nitrogen trifluoride
How Does Human Activity Play a Role in Greenhouse Gas Emissions?
Human activity plays a significant role in releasing greenhouse gases into the atmosphere. The increase of greenhouse gases in the atmosphere has contributed to rising global temperatures.
Water vapor has the highest concentration out of any of the greenhouse gases in our atmosphere. It does not always directly correlate to human activity, and its amounts can vary depending on regional meteorological conditions. However, as the global temperature rises because of increases in other greenhouse gases due to human activity, the atmosphere will become more humid, ultimately contributing to an increasing greenhouse effect.
Carbon dioxide is the greenhouse gas that is most emitted through human activity, accounting for about 74% of human caused emissions (73.8% in 2025, according to EDGAR). The burning of fossil fuels, including natural gas, is the primary cause of CO2 emissions.
Methane has more significant warming effects than carbon dioxide but does not remain in the atmosphere as long. Per ton, it traps roughly 80 times as much heat as CO2 over 20 years and about 27 to 30 times as much over 100 years, according to the IPCC’s current estimates. It accounts for about 17% of human caused emissions and is emitted due to agriculture, gas flaring, and the decay of organic waste in landfills. You can read more about what happens to gases in the atmosphere over time.
Nitrous oxide has even more significant warming effects than methane does, at roughly 270 times CO2 per ton over 100 years. It accounts for about 6% of human induced GHG emissions. Nitrous oxide is released due to agricultural and industrial practices.
Ozone is difficult to measure due to the short amount of time it exists in the atmosphere and its substantial differences in concentration around the globe. The ozone near Earth’s surface, called tropospheric ozone, acts as a warming greenhouse gas. It is produced through the burning of fossil fuels, like traffic emissions, and the burning of vegetation. It is a different issue from the thinning of the protective ozone layer, which you can read about in our guide to ozone depletion, and surface ozone is also an air quality problem, covered in our post on air pollution and climate change.
Fluorinated gases constitute roughly 2% of greenhouse gas emissions. These gases are a product of industrial practices, including the use of refrigerants, and do not occur naturally. They have greater warming effects per gram than any naturally occurring greenhouse gases. The shares of each gas above come from the World Resources Institute’s Climate Watch data.
How Are Greenhouse Gases Produced Naturally?
Water vapor, carbon dioxide, methane, nitrous oxide, and ozone are naturally produced. These gases allow for the greenhouse effect to keep the planet at a suitable temperature for life on Earth.
Water enters the atmosphere in vapor form when it evaporates from bodies of water around the world. As global temperatures increase, more water is evaporated into the atmosphere.
Carbon dioxide exists in the atmosphere as part of the natural carbon cycle. Volcanic activity, gas released from the oceans, decomposing vegetation, and wildfires contribute to carbon dioxide entering the atmosphere. Carbon sinks, like the ocean and rainforests, are responsible for naturally cleaning up the amount of carbon present in the air but are struggling to contend with the dramatic increases in quantity since the Industrial Revolution.
Natural sources of nitrous oxide and methane emissions include releases from wetlands, tundra, the ocean and its sedimentary layers, and soils under natural vegetation. As permafrost thaws, this natural source is growing, and NOAA’s Arctic Report Card has found that the Arctic tundra now releases more carbon than it absorbs.
Ozone is created when high energy ultraviolet sun rays alter oxygen.
What Is the Greenhouse Effect?
The greenhouse effect is how heat is trapped on the Earth before it can return to space. We receive radiation from the sun in the form of visible light, ultraviolet rays, and infrared radiation. Of these forms of radiation, 70% are absorbed into Earth’s landmasses, oceans, and atmosphere. The rest is reflected into space by light colored, reflective surfaces like clouds and ice.
As the surfaces of Earth absorb this radiation, they heat up, and some of that heat is then reflected into the atmosphere. As that heat travels through the atmosphere toward space, greenhouse gases absorb the heat radiation, trapping some of it before it can escape into space.
How Do Greenhouse Gases Cause Global Warming?
Greenhouse gases are responsible for global warming because they trap heat that would otherwise escape from the atmosphere. Unlike oxygen and nitrogen, these gases can absorb radiation and hold onto heat.
Greenhouse gases keep Earth at a temperature that can harbor life. If there were no greenhouse gases, the Earth would be much too cold for most life as we know it. On the other hand, if concentrations keep rising, more heat is trapped, the planet keeps warming, and the impacts on weather, sea levels, and ecosystems grow.
Let’s look into the industries and nations that are behind the greenhouse gases that cause global warming.
How Much Are Human Activities Responsible for Greenhouse Gas Concentrations?
Human activities play a big role in greenhouse gas emissions and concentrations. Activities like fossil fuel combustion and deforestation contribute to the amounts of greenhouse gases that remain in the atmosphere.
Carbon dioxide emissions are responsible for the majority of human contribution to greenhouse gas levels. Burning coal, oil, and natural gas emit significant quantities of carbon dioxide. Global greenhouse gas emissions grew 51% from 1990 to 2021, and they reached a record 55 billion tonnes of CO2 equivalent in 2025. Power generation is one of the biggest sources, which you can read about in our post on carbon dioxide emissions from electricity.
Land use change, like deforestation, has limited the amount of carbon dioxide removed from the atmosphere by trees. The issue is that the amount of GHG emissions has surpassed the Earth’s natural ability to absorb the gases from the atmosphere. The ocean and land together absorbed about half of human CO2 emissions over the past decade (about 29% and 21%), so the other half stays in the air. Now that the emissions increase faster than gases are removed, global temperatures will continue to rise as greenhouse gas concentrations increase.
What Sectors Cause the Most Greenhouse Gas Emissions?
Energy use is the number one source of greenhouse gas emissions, responsible for 75.7% of global emissions, according to the World Resources Institute. Road transportation alone accounts for 12.2% of global emissions. In 2025, power generation was the single largest sector, at nearly 30% of the total, and it was the only sector whose emissions fell that year, by 0.3%.
Here is how the major sectors break down:
- Energy (power, buildings, transportation, and fuel use in industry): 75.7%
- Agriculture: 11.7%
- Industrial processes and waste combined: about 10%
- Land use, land use change, and forestry: 2.7%
The US breakdown looks a little different. In the United States, transportation accounts for about 28% of greenhouse gas emissions and electric power for about 24%, and you can see the biggest sources in our list of the top 10 contributors to CO2 pollution in the US.
What Countries Are Responsible for the Most Greenhouse Gas Emissions?
Today’s biggest emitters are different from the countries that have emitted the most over time. According to EDGAR’s 2025 data, the three largest emitters of all greenhouse gases were:
- China, with 29.5% of the global total
- The United States, with 11.1%
- India, with 8.3%
They were followed by the EU (5.8%), Russia (4.8%), and Indonesia (2.5%).
The countries accountable for the most emissions between the years 1850 and 2021 are as follows:
- The United States is responsible for 20% of total emissions globally.
- China is responsible for 11% of that total.
- Russia has contributed 7% of that total.
In recent years, China has emitted the largest amounts of greenhouse gases. China’s coal use is shifting, though. Coal supplied about 54% of China’s electricity in 2025, down from 61% in 2020, according to Ember.
After China comes the United States. While the United States has attempted to turn away from coal burning to generate electricity, the nation is a large producer of crude oil and relies heavily upon fossil fuel use for transportation.
India comes in third. The nation’s emissions come primarily from burning coal for electricity, which supplied about 71% of its electricity in 2020.
How Can We Lower the Concentration of Greenhouse Gases in Our Atmosphere?
To lower the large concentrations of greenhouse gases, the world needs to work together to reduce the amount of greenhouse gas emissions occurring and work toward net zero emissions, where whatever is still emitted is balanced by removals from the atmosphere. While getting emissions to zero can’t happen overnight, we can continue to take strides in the right direction.
Switching to clean and renewable energy can reduce emissions of greenhouse gases. Individuals can take personal responsibility and make life decisions that will help lower their carbon footprints. Options like carbon offsets can help individuals and businesses address emissions they cannot yet cut. Let’s go over some of these options in more detail.
How Can Renewable and Clean Energy Help?
Renewable energy offers sources of power that can never run out. Most renewable sources release little or no greenhouse gas while generating power, and over their whole lifecycle they emit far less than fossil fuels. Renewable energy can be generated from solar, wind, hydro, geothermal, and biomass sources, and you can learn more in our guide to sustainable energy sources.
Clean energy is a low emission form of energy, but unlike renewable energy its fuel supply is finite. An example of this type of energy is nuclear power.
A large scale switch to renewable and clean energy could cut global emissions and give the natural sinks room to absorb some of the excess greenhouse gases in the atmosphere.
What Actions Can I Take to Help?
The best thing you can do is educate yourself about emissions and become aware of what actions you can take to participate in greenhouse gas mitigation. You can start by calculating your carbon footprint and then work on reducing the number. This may include:
- Choosing seasonal and local food when you can
- Eating less meat and other animal products
- Buying used clothing
- Buying from companies that report their emissions and reduction progress openly
- Being aware of your power and water usage at home
- Riding your bike or walking over driving
How Can I Use Greenhouse Gas Emission Offsets to Help the Global Climate?
Carbon offsets fund projects that reduce or remove greenhouse gases, such as planting trees, protecting forests, or capturing methane from landfills. An individual or business can purchase the amount they would like to put toward verified emission reductions or removals to address emissions they have not yet been able to cut. Offsets work alongside reducing your own emissions, not instead of it. See carbon offsets explained for the basics, learn the difference between a carbon offset and a carbon credit, and read how to find high quality offsets.
Terrapass offers a personal carbon offset or carbon offsets for your business that fund verified emission reductions and removals through projects around the world, certified against recognized standards.
FAQ: Greenhouse Gases
What are the main greenhouse gases?
Water vapor, carbon dioxide, methane, nitrous oxide, and ozone occur naturally, and synthetic fluorinated gases like HFCs, PFCs, and sulfur hexafluoride come only from human activity. Carbon dioxide makes up about 74% of human caused greenhouse gas emissions, methane about 17%, nitrous oxide about 6%, and fluorinated gases about 2%.
What is the greenhouse effect?
It is the process by which greenhouse gases absorb heat radiating from Earth’s surface and hold some of it in the atmosphere instead of letting it escape to space. Without it, the planet would average just under 0°F instead of about 57°F.
Are greenhouse gases always bad?
No. Natural greenhouse gases keep Earth warm enough to support life. The problem is that human activity has pushed concentrations well above preindustrial levels, with carbon dioxide now about 52% higher, trapping extra heat.
Which sector produces the most greenhouse gas emissions?
Energy, which includes power generation, transportation, buildings, and fuel use in industry, accounts for about 75.7% of global emissions. Agriculture adds about 11.7%. Power generation was the single largest sector in 2025, at nearly 30% of the total.
Which countries emit the most greenhouse gases?
In 2025 China emitted about 29.5% of the global total, the United States 11.1%, and India 8.3%. Counting everything emitted since 1850, the United States leads with about 20%, followed by China at 11% and Russia at 7%.
Are greenhouse gas emissions still rising?
Yes. Global emissions reached a record 55 billion tonnes of CO2 equivalent in 2025, up 0.9%, though growth is slowing and emissions from power generation, China, and India were flat or lower.
Can carbon offsets reduce greenhouse gases in the atmosphere?
Carbon offsets fund verified emission reductions or removals through projects, such as landfill gas capture or forest conservation. They work alongside cutting your own emissions, not instead of it.
Greenhouse Gases and the Future
Greenhouse gases are not all bad. After all, they maintain Earth’s temperature to keep it habitable. However, as concentrations of these gases continue to increase, we need to take action to keep them in check to avoid global warming and other negative impacts on our climate system.
Understanding humans’ role in global emissions and other climate impacts is an excellent first step toward curbing this problem we see before us. As we continue to understand how our actions impact our atmosphere, we can work toward a future where concentrations stop rising and the Earth’s natural process of greenhouse gas regulation can recover.
If you want to make a difference today, see how Terrapass carbon offsets fund verified emission reductions and removals, estimate your footprint with the free calculator, and keep learning on the Terrapass blog.
Sources for the 2026 data:
Argus Media, EDGAR 2025 global greenhouse gas emissions report
World Resources Institute, greenhouse gas emissions by country, sector, and gas
CSIRO summary of the Global Carbon Budget 2025
Carbon Brief, historical responsibility for climate change
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