To reach vital global warming targets, over 100 countries have promised to reduce their emissions to net zero by 2050. How can each and every one of us contribute to this massive challenge?

Q: Why is carbon such a problem?:

A: Levels of carbon dioxide (CO2) have been on the rise fairly steadily since the start of the Industrial RevolutionA period of sudden, rapid industrialisation that transforms a country from an agricultural to an industrial economy.. Human emissions have now risen to more than 35 billion metric tonnes per year. In fact, scientists now think that the last time there was this much CO2 in the atmosphereThe layer of gases surrounding a planet or moon, held in place by that planet's gravity. Small planets and moons have weak gravitational fields, and therefore only a very thin atmosphere. was three million years ago.

Gases like CO2 are heat-trapping, meaning they collect heat in the atmosphere just like the glass in a greenhouse. The more greenhouse gases, the less heat escapes at night, and the planet heats up. The Earth's average temperature has increased by roughly 1C since 1750.

Q: What is net zero?:

A: In 2015, countries met in France for a UNUnited Nations. An intergovernmental organisation based in New York that aims to maintain international peace and security. climate change conference. There, they adopted the Paris Agreement. Part of this included a goal to limit global warming to 1.5C, and one of the most ambitious plans for achieving this was to reduce emissions to net zeroWhen the gases going into the atmosphere are balanced by those being taken out of it..

Lots of our daily activities like driving a car, heating our homes and eating a burger emit greenhouse gases like CO2 and methaneA particularly strong greenhouse gas produced by fossil fuels and cattle.. But carbon can also be absorbed by the Earth through grass, peatlands and the ocean. Net zero means that we will be putting the same amount of greenhouse gases into the air as we take out.

Q: Which countries have made the promise?:

A: More than 100 have committed to becoming carbon neutral by 2050. Many include major emitters such as the UK, Japan and South Korea. Plus, the US hopes to rejoin the Paris Agreement once Joe Biden takes office.

China also plans to get to net zero by 2060. Responsible for 28% of the world's greenhouse gas emissions, it will need to reduce its carbon by up to 90%. But many have hope because of the infrastructureThe basic systems and services that a country needs to keep it going. already in place. One out of every three solar panels on the planet is in China, it is home to the largest hydroelectric dam in the world and 98% of its buses are electric.

Q: How can individuals help?:

A: One of the biggest ways to reduce your carbon footprint is to rethink how you travel. Jo Hand is an activist who runs a company helping people live sustainably. She advises taking public transport instead of driving, as well as walking or cycling whenever possible. But, according to her, the "biggest win" would be to cut out flying, which produces far more CO2 than any other form of transport.

Another way to make a difference is by changing how you shop. Choose to repair and recycle old clothes rather than buying new ones. Check the food miles on what you eat, and try to go to local shops as much as possible.

Q: What about offsetting?:

A: Countries, companies and individuals can all invest in offset schemes that remove the carbon created by their activity. For example, if you pay to offset a flight that you take, you can be sure that, somewhere, the carbon your flight released has been balanced out by a scheme to remove it.

The most popular offsetting activity is planting trees. It is the simplest and cheapest way to create a carbon sink. However, most experts agree that we cannot succeed simply by investing in trees and
peat bogs. Taking responsibility to reduce our own carbon is just as important.

Q: Will net zero be enough?:

A: Some think no. In an open letter written in November last year, a group of public figures including Dr Rowan WilliamsThe former Archbishop of Canterbury. and Dr Shahrar AliA British politician and former deputy leader of the Green Party. wrote an open letter urging companies and governments to go further. "No matter how quickly we reach zero emissions," they wrote, "the terrible impacts of the climate crisis will not just go away."

Others are more optimistic. One recent study found that if the 100 countries succeed in their promise to go carbon neutral, global warming will slow down dramatically. And, as one lecturer from Imperial College London says, once that target is reached, reducing will be much easier.

Industrial Revolution - A period of sudden, rapid industrialisation that transforms a country from an agricultural to an industrial economy.

Atmosphere - The layer of gases surrounding a planet or moon, held in place by that planet's gravity. Small planets and moons have weak gravitational fields, and therefore only a very thin atmosphere.

UN - United Nations. An intergovernmental organisation based in New York that aims to maintain international peace and security.

Net zero - When the gases going into the atmosphere are balanced by those being taken out of it.

Methane - A particularly strong greenhouse gas produced by fossil fuels and cattle.

Infrastructure - The basic systems and services that a country needs to keep it going.

Dr Rowan Williams - The former Archbishop of Canterbury.

Dr Shahrar Ali - A British politician and former deputy leader of the Green Party.