In this article we take a look at the sectors that are responsible for the largest proportions of CO2 emissions around the world, and steps we can take to reduce them. 

Sources: World Resources Institute and Environmental Protection Agency

1. Electricity and heat production 

The burning of fossil fuels (coal, natural gas, and oil) for electricity and heat is, by far, the main driver of climate change. This sector makes up the largest single source of global greenhouse emissions at 25% of all emissions. Of this, roughly a third goes to residential and commercial electricity and heat, a third to transportation and a third to industry, with the remainder being used on agriculture.

How can we reduce this?

• Replacing fossil fuels with renewable energy sources (such as wind, solar, and hydro) to generate electricity. This is by far the most sustainable and environmentally conscious option.
• Switching to less-carbon intensive fuels
• Generating electricity from nuclear energy instead of fossil fuel combustion
• Carbon capture – This means capturing the CO2 released in combustion before it enters the atmosphere and burying it underground

2. Transportation

The transportation sector includes the movement of goods and people by cars, planes, trucks, ships, trains, and other vehicles. The pollution produced comes mainly from burning petroleum-based products like petrol and diesel, and makes up 14% of global emissions. 

How can we reduce this? 

• Fuel switching – this means using fuels that emit less CO2 than the fuels currently being used. For example, biofuels, hydrogen, and electricity from renewable sources are all good alternatives that are better for the environment. 
• Reducing the amount of people travelling would also mean less fuels burned. This involves a cultural shift of encouraging people to fly and drive less, and walk and cycle instead. 

3. Industry 

Industry accounts for 21% of global greenhouse gas emissions. This sector produces all the goods and raw materials we use every day. 

How can we reduce this? 

• Recycling- If we produced industrial products from materials that are recycled or renewable, rather than making new products from raw materials, this number would be significantly decreased.
• Switching to fuels that result in less CO2 emissions to run machinery in factories e.g. natural gas instead of coal. 
• Making industry more energy efficient to use less heat and light day to day. 

4. Agriculture

Agricultural activities including crop and livestock production for food contribute 11.8% of global greenhouse gas emissions. 

How can we reduce this?

• Swapping to a plant-based diet would reduce the pressure on livestock for the meat and dairy industry, as well as requiring less crops to feed animals. 

5. Buildings and waste

The commercial and residential sectors include all homes and commercial businesses. This accounts for roughly 9.2% of global emissions. In this sector, the greenhouse gas emissions come from burning fossil fuels for heating and cooking, waste management, and the electricity consumed by homes and businesses. 

How can we reduce this?

• Making homes and commercial buildings more energy efficient includes improving insulation, better ventilation, and more energy efficient appliances. Going forwards, buildings and homes need to be designed with energy efficiency in mind to minimise greenhouse gas emissions. 
• Reducing the amount of waste sent to landfill. When waste decomposes in landfill, methane and CO2 are released. To combat this as a society we need to send less to landfill through recycling and reducing consumption, as well as investing in methane capture to prevent the gas from going into the atmosphere.

6. Deforestation 

The cutting down of our forests for fuel and to make room for crops contributes 6.5% of global emissions. This is catastrophic for our climate as trees when alive take in carbon dioxide from the atmosphere.This is known as sequestration. When plants are burned, CO2 is released into the atmosphere, and there is less opportunity for CO2 sequestration. 

How can we reduce this?

• Reducing the rate of deforestation by protecting plant lands worldwide. 
• Reforesting areas of forest that have been cleared to reintroduce plants for carbon capture
• Minimising the conversion of forest land to other uses such as crops, either by reducing the demand for crop plants or imposing limits on this kind of land use.