Carbon markets incentivize companies to cut emissions but require high carbon prices

Carbon sinks absorb more greenhouse gases than they produce

The largest on Earth are oceans, which capture 25% of all carbon emissions and 90% of excess atmospheric thermal radiation while generating half of the world's oxygen. Wildfires and deforestation have reduced forests' net sink capacity, though fungi are believed to capture and store over a third of global carbon emissions.

Greenhouse gas removal consists of a series of techniques to capture and store GHGs

These include turning biomass into charcoal for storage in soil before it decays and releases carbon dioxide, crushing CO₂-absorbing rocks—increasing exposed surface area—and spreading them across land to accelerate GHG uptake, and restoring degraded peatlands, which can store twice the amount of carbon as the average forest.

While carbon capture and storage systems collect carbon dioxide at the source, such as power plants, direct air capture systems extract it from the atmosphere.

How a black market for banned refrigerants still threatens ozone recovery and climate progress

Despite the Montreal Protocol's success, illegal trade in chlorofluorocarbons, hydrochlorofluorocarbons, and hydrofluorocarbons persists. Driven by high profits and weak enforcement, smugglers supply banned refrigerants, causing significant ozone depletion and greenhouse gas emissions equivalent to billions of tons of carbon dioxide.

What’s the best way to reduce climate impact of food?

Food is a big part of everyone’s carbon footprint, and it’s important to understand the impact of our personal food consumption. Individual food choices can emit as many greenhouse gases as personal electricity use. Plant-based diets generally...

The Montreal Protocol helped prevent significant quantities of greenhouse gas emissions

By phasing out ozone-depleting chemicals between 1990 and 2010, the Montreal Protocol prevented emissions equal to 135 gigatons of CO₂—avoiding an estimated 0.5 to 1 degrees Celsius of additional global warming by 2100.

Explore an interactive visualization of greenhouse gas emissions from 745 million sources worldwide.

Why a Montreal Protocol amendment cut back on the replacements for CFCs

Hydrofluorocarbons were introduced in the 1990s as ozone-safe substitutes for chlorofluorocarbons and hydrochlorofluorocarbons. However, scientists later found that they trap thousands of times more thermal energy in the atmosphere than carbon dioxide does, prompting a 2016 amendment to the Protocol to phase them out.

How greenhouse gases and climate change impact the efficiency of photosynthesis

A review in the Journal of Experimental Botany found that higher temperatures reduce the efficiency of enzymes involved in photosynthesis and impair a plant's ability to control water loss and regulate carbon dioxide uptake. While increased carbon dioxide levels are understood to accelerate plant growth by boosting photosynthesis, researchers suggest these effects more than offset the potential gain.

When signing the Paris Agreement, almost 200 nations committed to pursuing efforts to limit global warming to 1.5 degrees Celsius above preindustrial levels, based on guidance from the Intergovernmental Panel on Climate Change.

Yearly greenhouse gas emissions have been steadily increasing since 1850

Although greenhouse gases include methane, nitrous oxide, and most fluorinated compounds, their warming potential is often measured relative to carbon dioxide. In these units, greenhouse gas emissions have gone from 4.29 billion metric tons of carbon dioxide equivalent in 1850 to 54.43 billion metric tons in 2024.

Greenhouse gas emissions from human activity accelerate recent global warming

These gases exacerbate the greenhouse effect—warming that results when the atmosphere traps heat radiating from Earth toward space. The most abundant atmospheric greenhouse gas is carbon dioxide, which is released from the burning of fossil fuels.

Carbon dioxide is the most produced greenhouse gas from human activities

In 2022, about 79.7% of US greenhouse gas emissions were carbon dioxide, produced through chemical reactions in processes such as cement production and the burning of fossil fuels, solid waste, trees, and other biological materials. Methane (11.1%), nitrous oxide (6.1%), fluorinated gases (3.1%), and trace amounts of solid and liquid aerosol were also created.

The impact of greenhouse gases is assessed as a measure of Global Warming Potential

Since 1990, the Intergovernmental Panel on Climate Change has used GWP to measure how much energy 1 metric ton of a gas emits over a given period—usually 100 years—relative to 1 metric ton of carbon dioxide. By definition, carbon dioxide has a GWP of 1.

The Supreme Court curbed the EPA's power to regulate carbon emissions in 2022

In West Virginia v. EPA, the Supreme Court ruled 6-3 that the EPA exceeded its authority by requiring industrywide carbon cuts. Chief Justice Roberts' opinion invoked the "major questions" doctrine, which limits the ability of federal agencies to act without explicit congressional approval.

The world's wealthiest 10% are responsible for 48% of greenhouse gas emissions

An analysis by the International Energy Agency found that in 2021, the top 1% of emitters each produced over 50 metric tons of carbon dioxide, over 1,000 times the amount produced by those in the bottom 1%. The average energy-related carbon footprint, including household heating and electricity use, was about 4.7 metric tons per person.

What should you eat to help the climate?

Climate change is impacted by what we eat and what we don't eat. Did you know, for instance, that livestock accounts for 14.5 percent of the world’s greenhouse gases each year? Eating less meat and dairy and more protein-rich plants like beans,...

How the Montreal Protocol made CFCs the most valuable Miami contraband after cocaine

Following the 1990s production ban, smugglers flooded Miami with illegal chlorofluorocarbons used in air conditioning. A 15-kilogram cylinder bought for $70 in Europe could sell for $242 in the US, fueling multimillion-dollar black-market trade. (Some users may experience a paywall.)

Carbon dioxide acts as a 'control knob' for Earth's climate

Although Earth's ice ages were primarily triggered by slow changes in the planet's orbit—known as Milankovitch cycles—these changes do not explain the extreme temperature swings during glacial periods. Carbon dioxide acts as a feedback mechanism, intensifying both cooling during ice ages and warming during their ends by reinforcing the initial changes sparked by orbital shifts.

Greenhouse gas emissions from human activities have contributed to global warming

A 2021 report from the Intergovernmental Panel on Climate Change found that such emissions were responsible for approximately 1.1 degrees Celsius (2.0 degrees Fahrenheit) of warming since 1850-1900. Without rapid, large-scale reductions in emissions, temperatures are expected to continue to rise, leading to more extreme weather events.

Methane leaks during natural gas processing reduce the gas's overall cleanliness

Natural gas is advertised as a cleaner fossil fuel because it emits 50% less carbon dioxide than oil and coal when burned. Supporting analysis only considers end-use combustion and excludes total emissions generated by extraction, shipping, and processing.

As of 2024, China is the largest overall contributor to global greenhouse gas emissions

Due to its large population, the nation's per capita emissions continue to lag behind those of the US, Canada, Russia, Australia, and Saudi Arabia. The Arab country has experienced the most significant increase in per capita greenhouse gas emissions since 1990, now leading the world at 22.8 metric tons of carbon dioxide equivalent per capita.

Methane: the other greenhouse gas

While most of the focus with respect to greenhouse gases lands on carbon dioxide, methane is the second most potent contributor. The gas, a carbon atom with four hydrogen atoms, is 25 times more potent than CO2 in terms of trapping heat over a 100...

The food industry's hard-to-solve pollution

One-quarter of the world's greenhouse gas emissions result from food and agriculture. That whopping number includes production and post-farm processes like distribution. See a visualization of the data along with a breakdown explaining how each process contributes to emissions, and why it’s so difficult to improve the agriculture industry.

Explore which sectors produce the most greenhouse gas emissions by country

As of 2023, the energy sector, including electricity and heating, accounts for the largest share of greenhouse gas emissions. The 10 largest greenhouse gas-emitting nations account for two-thirds of global emissions, with the world's top three—China, the US, and India—contributing 15 times more than the bottom 100.

Feeding grazing cattle seaweed cut their methane emissions by almost 40%

The largest share of the 12% of global greenhouse gas emissions from livestock comes from methane released when cows burp. A study found that introducing a seaweed supplement in pellet form significantly reduced these emissions without affecting cattle's health or weight.

Understanding the 1.5 degree Celsius climate benchmark

As more parts of the world are facing extreme weather, from high temperatures to increased natural disasters, there is much debate about what can be done. MIT News explores and explains the 1.5-degree benchmark for limiting the effects of climate change. Read to understand where the planet stands in relation to this threshold and what can be done at the global, regional, and personal levels to “keep 1.5 alive.”

Arctic permafrost may store twice as much carbon as the entire atmosphere

Rising greenhouse gas concentrations are expected to continue to increase average global temperatures and threaten to thaw ground that has been frozen for thousands of years. The release of greenhouse gases from remnant organic matter would exacerbate the greenhouse effect, creating a positive feedback loop.

Greenhouse gases from farming are driven by meat

The food we eat contributes to one-third of global greenhouse gas emissions caused by human activities, according to two studies published in 2021. These emissions come from various sources along the food production chain, including transportation,...

Artificial photosynthesis turns CO₂ into sustainable fuel

Carbon conversion focuses on a central perplexing question: if carbon dioxide is a leading driver of climate change, and fossil fuels are made of carbon-based molecules, can we devise a way to convert CO₂ into useful alternatives efficiently? This video breaks down a potential pathway using artificial photosynthesis, which uses sunlight to convert CO₂ into fuel.

Excluding water vapor, greenhouse gases make up less than 1% of Earth's atmosphere

Although carbon dioxide, methane, nitrous oxide, ozone, and most fluorinated gases account for only a minority of the planet's greenhouse effect due to their lower concentrations, they are more effective at trapping thermal radiation. While water vapor condenses within two weeks, other greenhouse gases linger in the atmosphere for years on average.

Establishing the wind power grid required incentives, reliability, and affordability

Although wind was harnessed to generate electricity for individual buildings in the late 1800s, high costs, mechanical issues with turbines, and better fossil-fuel alternatives delayed wind power's widespread growth. After the oil crises of the 1970s, governments sought alternative energy sources and, in the decades that followed, provided tax credits to expand the wind power market.

China's tree belt around the Taklamakan Desert has become a carbon sink

Decades of planting trees along the Taklamakan Desert in northwest China (the world's largest shifting-sand desert) have increased vegetation enough to create a measurable carbon sink, absorbing more carbon dioxide than the area emits. The effort demonstrates a key large-scale climate mitigation strategy, though it has raised concerns over water use and long-term sustainability.

Unless prices of fossil fuels rise significantly, their production is expected to slow

US oil and natural gas production skyrocketed from 2000 to 2020, largely due to advances in fracking. However, weak global energy prices have prevented this boom from translating into increased profits for fossil fuel companies.

Cryptocurrency is reshaping finance, but its environmental impact often sparks debate

Behind the scenes, mining operations consume vast amounts of energy, comparable to the emissions of small nations. What drives this surprising environmental footprint, and can the industry evolve?

How amendments to the Montreal Protocol have expanded global ozone protections

Since 1990, five major amendments—London, Copenhagen, Montreal, Beijing, and Kigali—have accelerated chemical phase-outs, added new substances, such as hydrochlorofluorocarbons, and tightened enforcement.

How Earth's 'greenhouse effect' works

The so-called "greenhouse effect," where various gases in Earth's atmosphere trap heat from the sun, is a crucial factor in our planet's ability to sustain life. It's also pivotal in discussions over humanity's impact on changes in the Earth's...

Stock buybacks are when a company purchases some of its own shares of stock

This reduces the number of shares on the market and, therefore, makes the remaining shares more valuable. Buybacks have received a lot of criticism in recent years for many reasons, such as how they could artificially inflate share prices.

Determine your carbon footprint using the Environmental Protection Agency's Carbon Footprint Calculator, which incorporates various emission factors involving home energy, transportation, and water production.

Without greenhouse gases, Earth's average surface temperature would be below freezing

Atmospheric molecules that absorb and emit infrared radiation from the planet's surface effectively trap additional incident solar energy that would otherwise escape to space. Without the greenhouse effect, the planet's average surface temperature would be approximately -18 degrees Celsius (0 degrees Fahrenheit).

Across a 20-year period, methane has more than 80 times the warming potential of CO₂

However, this greenhouse gas lasts only about 12 years in the atmosphere, much less than the centuries or more that carbon dioxide can persist. Methane is produced primarily during the production, storage, and transmission of coal, natural gas, and oil, as well as from the digestive processes of domestic livestock.

Watch a demonstration of the greenhouse effect with carbon dioxide, where thermal energy is trapped by the gas within a container, causing the temperature to increase.

Global climate models simulate Earth system interactions and how human activity impacts climate

By splitting the planet into tiny 3D grid cells, supercomputers can run thousands of equations for each cell to determine the movement of energy, moisture, and other elements across Earth. The equations can also incorporate greenhouse gases to determine how humans affect the climate.

Cryptocurrency and data center growth are expected to increase greenhouse gas emissions

An analysis from the Open Energy Outlook Initiative estimates a 30% increase in emissions through 2030, as growing energy demands in regions where data centers are being built (20%-30%) far exceed the traditional growth rate of utilities in those areas (1%-2%). The emissions spike is expected to equal France's annual carbon output.

Climate resilience strategies, which help communities mitigate the effects of climate change, include painting roofs white, building clam gardens, harvesting fog, and feeding cows seaweed.

Commodity trading is regulated by the CFTC to mitigate fraud and risk

Established in 1974, the CFTC regulates these markets (including swaps, futures, and certain types of options) to protect market participants from fraud, ensure fair trading conditions, and generally reduce financial risk.

Large oil companies knew about the impact of carbon emissions since the ’70s

PBS Frontline’s The Power of Big Oil reveals how industry giants like Exxon and Shell were researching climate change in the 1970s but then funded denial campaigns—using internal science to sow public doubt for decades.

Policymakers make complex trade-offs when considering tariffs—while they can generate government revenue and encourage the consumption of locally produced goods, they can also lead to higher consumer prices and may negatively impact economic growth.

Energy Star certifies efficiency to help Americans save energy and cut emissions

Launched by the EPA in 1992, the Energy Star program identifies appliances, buildings, and electronics that meet high efficiency standards. It has helped consumers save over $500B in energy costs and prevent 4 billion metric tons of greenhouse gas emissions.

Why decarbonizing the entire electric grid is impossible with its current infrastructure

Fossil fuel plants can be built anywhere and have thus typically been built near highly populated areas, such as coastal cities, where electricity demand is high. However, certain renewable resources operate most efficiently in specific regions, such as wind turbines in the Midwest, and therefore require substantial transmission infrastructure to be constructed to transport the generated electricity.