How Does Carbon Affect Global Climate Change?

Climate change refers to significant changes in global temperature and weather patterns occurring over an extended period. While the Earth’s climate has undergone natural fluctuations for millennia, the current period of climate change is occurring at a rapid rate, primarily driven by human activities like burning fossil fuels. One of the key factors implicated in contemporary climate change is the greenhouse gas carbon dioxide (CO2). Carbon dioxide and other greenhouse gases like methane and nitrous oxide trap heat in the atmosphere through a phenomenon called the greenhouse effect. This leads to global warming and related climate impacts.

Carbon is emitted into the atmosphere by natural sources like volcanoes and decomposing organic matter, and by human activities like burning fossil fuels, manufacturing cement, and deforestation. This disrupts the natural carbon cycle, where carbon circulates between the atmosphere, oceans, ecosystems, and geologic stores. By extracting and burning fossil fuel reserves accumulated over millions of years, human activities have caused carbon dioxide concentrations in the atmosphere to rise dramatically over the industrial age. Today, atmospheric carbon dioxide levels are higher than at any point in the past 800,000 years. The elevated concentrations of greenhouse gases like carbon dioxide are enhancing the greenhouse effect, driving radiative forcing that results in climate change.

Carbon’s Greenhouse Effect

Carbon dioxide (CO2) and other greenhouse gases like methane (CH4) and nitrous oxide (N2O) are able to absorb infrared radiation emitted from the Earth’s surface. As incoming solar radiation warms the Earth’s surface, the surface emits infrared radiation to release the heat back into the atmosphere. Greenhouse gases like CO2 trap this heat by absorbing the infrared radiation. This causes more heat to be retained in the lower atmosphere rather than escaping into space. Without the natural greenhouse effect, the average global temperature would be about 60°F colder.

Human activities like burning fossil fuels for energy and transportation have greatly increased the levels of carbon dioxide and other greenhouse gases in the atmosphere over the past century. This has amplified the natural greenhouse effect, leading to increased radiative forcing that is causing global temperatures to rise. Radiative forcing is a measure of the change in energy balance between incoming and outgoing radiation caused by changes in greenhouse gas levels. Positive radiative forcing due to increased greenhouse gases will heat up the Earth’s surface and lower atmosphere. The increased greenhouse effect from human-generated carbon dioxide is the main driver of observed climate change since the mid-20th century.

Sources of Carbon Emissions

Three main sources account for the majority of carbon emissions contributing to climate change: fossil fuel combustion, deforestation, and industrial processes.

Fossil fuels like coal, oil, and natural gas release carbon dioxide and other greenhouse gases when burned to generate electricity, heat homes and businesses, power vehicles, and manufacture goods. The use of fossil fuels has increased dramatically since the Industrial Revolution, driving a rapid rise in atmospheric carbon. Fossil fuel emissions now make up over 75% of total greenhouse gas emissions from human activities.

Deforestation and changes in land use also play a major role. Forests naturally absorb and store carbon through photosynthesis. When forests are logged or burned down to make way for farms, housing, or industry, much of that carbon is released. Tropical deforestation in regions like the Amazon also reduces forests’ future capacity to remove carbon from the air.

Certain industrial processes like cement and steel production, waste management, and the use of fluorinated gases in refrigeration release additional carbon emissions. While smaller than the previous two categories, these industries account for around 15% of global greenhouse gas emissions.

The Carbon Cycle

burning fossil fuels like coal and oil releases carbon dioxide emissions that contribute to climate change.

Carbon cycles between the atmosphere, oceans, ecosystems and geosphere in different forms. The most well-known processes in the carbon cycle that move carbon between reservoirs are photosynthesis and respiration, ocean absorption, and carbon sequestration in sinks.

During photosynthesis, plants use sunlight to convert carbon dioxide from the atmosphere and water into glucose, releasing oxygen as a byproduct. This process removes carbon from the atmosphere and stores it in organic plant matter. Respiration converts organic matter back into carbon dioxide, releasing carbon back into the atmosphere or water.

The oceans can absorb massive amounts of carbon dioxide from the atmosphere. Carbon dioxide dissolves into the ocean where it reacts with water molecules to form carbonic acid. Ocean waters can then transport dissolved carbon dioxide further into the depths of the ocean. Over long timescales, carbon is stored in marine sediments.

Carbon is also sequestered and stored long-term in carbon sinks like forests, peatlands, and soils. Forests alone absorb roughly 2 billion tonnes of carbon dioxide each year. Peatlands are wetland ecosystems that absorb and store carbon in peat. Agricultural soils are estimated to contain around 2,500 gigatons of carbon globally.

Historic Carbon Levels

The amount of carbon in Earth’s atmosphere has fluctuated over time. Prior to the industrial revolution around 1750, atmospheric carbon dioxide levels remained around 280 parts per million (ppm) for several thousand years. This period from around 8,000 BCE to 1750 CE is known as the pre-industrial level.

Since the industrial revolution began in the mid-1700s, atmospheric carbon dioxide levels have risen sharply. The burning of fossil fuels like coal, oil and gas releases carbon dioxide into the air. Deforestation also contributes to rising carbon levels. In 2013, atmospheric carbon crossed 400 ppm for the first time in over 800,000 years. Today, carbon dioxide levels are around 415 ppm and continue to rise at over 2 ppm each year.

This rapid increase in atmospheric carbon dioxide levels over the past 250 years is almost entirely due to human activities. The pre-industrial baseline shows that recent carbon levels are extraordinarily high and abnormal compared to the past 800,000 years.

Impacts on Climate

Human carbon emissions are dramatically impacting global climate by causing rising temperatures, melting ice, sea level rise, and extreme weather events.

Global average temperatures have increased by about 1.8°F since the late 19th century, with most of the warming occurring in recent decades. The years 2016, 2019 and 2020 were the warmest on record. Higher global temperatures lead to widespread melting of snow and ice, which exposes darker surfaces that absorb more sunlight and cause more warming.

Warming temperatures are causing severe melting of Arctic sea ice. In September 2020, Arctic sea ice reached its second lowest extent on record. Melting glaciers and ice sheets are contributing substantially to sea level rise. Between 2006 and 2015, the Greenland Ice Sheet lost ice mass at an average rate of 278 billion tons per year.

Rising ocean temperatures are causing seawater to expand, which along with melting land ice has caused global mean sea level to rise by about 8–9 inches since 1880. Higher sea levels amplify storm surge flooding during hurricanes. Globally, extreme weather events such as heatwaves and heavy precipitation have also increased in frequency and severity due to climate change.

Effects on Ecosystems

Rising carbon dioxide levels are profoundly impacting ecosystems around the world. As the climate warms, climate zones are shifting towards the poles and to higher elevations. This is causing disruptions as species attempt to migrate to more suitable habitats. Many species simply do not have the ability to shift their geographic ranges fast enough to keep pace with the changing climate.

Climate change and shifting habitats put many species at an increased risk of extinction. Species that live in fragile ecosystems like coral reefs and alpine regions are especially vulnerable. Ocean acidification from excess carbon dioxide is damaging marine ecosystems, putting coral reefs, shellfish, and phytoplankton populations at risk.

On land, warming temperatures and changing precipitation patterns are altering forests, grasslands, and freshwater ecosystems. As climate zones shift poleward, many species may lose their historical habitats. The rapid pace of climate change risks overburdening the ability of many species to adapt naturally.

Human Impacts

Rising carbon levels and climate change have wide-ranging impacts on human health and societies around the world. Some key human impacts include:

Health Effects

Higher temperatures and increased frequency of heat waves lead to heat-related illnesses and deaths, especially among vulnerable populations like the elderly, children, outdoor workers, and those without access to air conditioning. Climate change also expands ranges for diseases like malaria, dengue fever, Lyme disease, and hantavirus as insect and tick vectors spread to new areas.

Food and Water Security

Carbon emissions disrupt rainfall patterns and cause drought, reducing crop yields and threatening food supplies. Sea level rise leads to saltwater intrusion into freshwater supplies. Melting glaciers reduce water availability for over 1 billion people worldwide.


Rising seas, coastal erosion, more intense storms, and flooding displace millions from their homes, becoming climate refugees. Low-lying island nations face complete loss of land area from sea level rise.

Economic Costs

Climate change causes over $300 billion per year in economic losses globally, damaging infrastructure, disrupting supply chains and trade, reducing productivity, and more. Developing countries that contributed little to climate change suffer some of the worst impacts.

Mitigation Strategies

There are several ways we can mitigate climate change by reducing our carbon emissions and removing carbon from the atmosphere. Some key strategies include:

Renewable Energy

Transitioning from fossil fuels like coal, oil and natural gas to renewable energy sources like solar, wind, geothermal and hydroelectric power. Renewables create little to no carbon emissions, so increasing their share of global energy production can significantly reduce emissions.


Improving energy efficiency in buildings, transportation and industry can reduce energy usage and carbon emissions. Strategies like weatherization, high-efficiency appliances, hybrid/electric vehicles, and optimized industrial processes conserve energy.

Carbon Pricing

Implementing carbon pricing systems like carbon taxes and cap-and-trade puts a cost on carbon emissions, incentivizing reductions. It makes polluting energy sources more expensive while driving investment in clean alternatives.


Planting new forests removes carbon dioxide from the atmosphere through photosynthesis. Reforestation programs, especially in tropical regions, are an effective carbon removal strategy. Forest management and anti-deforestation policies also help preserve carbon sinks.


In summary, carbon dioxide is a major contributor to climate change due to its heat-trapping greenhouse effect. While CO2 exists naturally in the atmosphere, human activities like burning fossil fuels have increased carbon levels dramatically over the past century. This excess carbon has caused global temperatures and sea levels to rise, altered precipitation patterns, and disrupted ecosystems around the world. Addressing climate change will require reducing carbon emissions through an energy transition and better land management. Individuals can help by conserving energy, choosing clean transportation, and supporting climate-friendly policies. With diligent mitigation efforts, we may still curb the most dangerous impacts of climate change. But action is urgently needed to protect our planet’s future.

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