What You’ll Learn In This Module

• How much greenhouse gas is emitted each year?
• Which countries emit the most carbon dioxide today?
• Which countries have emitted the most carbon dioxide in total?
• Which countries emit the most greenhouse gases per person?
• What factors determine how much greenhouse gas a country emits?
• How much can developing countries be expected to reduce their emissions?
• Do the first-movers in emission-reduction stand to lose out?
• What is net zero? and which countries have a net zero target?
• What is the difference between net zero and carbon neutral?
• How close are we to net zero emissions?

How much greenhouse gas is emitted each year?

Adding all the different greenhouse gases together, about 51 billion tonnes of CO₂ equivalents are being emitted per year.

It’s estimated that over 1.5 trillion tons of carbon dioxide have been released into the Earth’s atmosphere since the start of the industrial revolution. These are causing climate change.

In 2019, about 37 billion tons of CO₂ were emitted. That’s 50% more than in the year 2000 and almost three times as much as 50 years ago.

The graph below shows you how annual emissions of CO₂ have continued to rise for many years.

But to reduce global temperatures and stop climate change, they need to fall to net zero.

In 2020, annual emissions did start to fall, as a result of the global pandemic.

While early data suggest that this was just a short-lived effect, it shows it’s possible for us to start making significant emission reductions today.

Which countries emit the most CO₂ today?

While all countries broadly agree that emissions need to fall, they do not fully agree on which countries are responsible for global greenhouse gas emissions.

They also don’t fully agree on which countries will have to reduce their carbon emissions most in the future.

The international politics of climate change is complicated.

This is in part because the global picture of emissions production has changed over time.

It’s also in part because the story changes depending on which measure of emissions you look at.

Consider a first measure – annual CO₂ emissions.

Taking the chart above and breaking it down by world region, you can see where CO₂ emissions were produced each year.

You can get a closer view by considering one year – for example, 2017, which is presented in the image below.

It shows that there were around 36 billion tons of global CO₂ emissions released in 2017.

Asia produced over half of them in that year.

China was the largest emitter, releasing nearly 10 million tons of CO₂, or 27% of global emissions.

The USA was the second-largest emitter, discharging 15% of global emissions.

Followed by the EU, which unleashed 10% of global greenhouse gases.

Together, China, the US and the EU produced more than half of the world’s CO₂ emissions.

And 10 countries or regions were responsible for 75% of global greenhouse gas emissions in that year.

These numbers highlight how important it is that the largest emitters are willing to reduce their emissions.

And also that they take action to reach net zero as soon as possible.

But the consideration of annual CO₂ emissions alone doesn’t tell you the full story.

Which countries have emitted the most CO₂ in total?

Consider a second measure, the total emissions produced over time, which gives you the historical picture of emissions, and the picture changes dramatically.

This measure shows that the US has emitted nearly 400 billion tons of CO₂, close to 25% of the world’s historical emissions. Most of this was in the 20th century.

The EU was responsible for 22% and China for 12% of greenhouse gases.

You can find the full global map below.

Which countries emit the most greenhouse gases per person?

The more people living in a country, the higher the total greenhouse gas emissions. You might want to zoom in to take a close look at the behaviour of individual people, like you.

A third important measure is the total historical numbers of CO₂ emissions divided by a country’s population size, which is the average emissions per person.

This measure shows that the largest CO₂ emissions per person are found in some of the world’s largest oil and gas producers.

But the numbers for these countries are very unstable and have been jumping around, depending on the amount of oil and gas being produced.

People in Australia emitted 17 tons of CO₂ per person on average in 2017, that’s three times the global average of 5 tons.

Close behind were people in the US and Canada. They produced 16 tons per person.

And the average German produced 10 tons per person.

The image below shows the picture for the whole world in 2020.

What factors determine how much greenhouse gas a country emits?

A comparison of different measures points to two important drivers of increasing greenhouse gas emissions and climate change. An increasing standard of living and land-use change.

(i) Standard of living.

Economic development is closely linked with energy production.

Around three-quarters of global greenhouse emissions come from countries with high levels of energy production and a high concentration of industry processes and transport.

These are not evenly distributed around the world because of the unequal distribution of industry and wealth.

Historically, the industrialized countries have emitted much more than the developing countries.

High historical emissions are linked to the industrial revolution and the earliest countries to industrialize their economies.

Wealth is also one of the strongest indicators of our individual carbon footprint.

As we get richer as individuals, we gain access to more goods and services to consume.

These include electricity and heating, air conditioning, lighting, consumer goods, cars and planes.

These have all been predominantly powered by fossil fuels, increasing the emissions we produce.

For example, the enormous rise in China’s CO₂ emissions over the last decade is coupled with a huge decrease in poverty.

(ii) Land-use changes

Around 25% of global CO₂ emissions are the result of land-use changes.

These typically come from cutting down or burning forests to clear the land and prepare it for agriculture, cities and roads.

When large areas of rainforests are cut down, carbon dioxide is released into the atmosphere. The land also often turns into less productive grassland with a reduced capacity to store CO₂.

South America, Asia and Africa are responsible for over 90% of present-day land-use change emissions.

In terms of the amount of CO₂ emitted, industrial processes still significantly outweigh land-use changes. But both play a part.

How much can developing countries be expected to reduce their emissions?

This question raises important ethical questions.

Many of today’s richest countries became rich from centuries of fossil fuel burning and industrial production.

These countries are now taking steps to reduce greenhouse gas emissions, for example by using less fossil fuels and more renewable energy.

But their annual emissions are starting to be dwarfed by other countries, especially China, who are emitting much more CO₂ as they get richer.

Rapidly developing countries such as China, India, South Africa and Brazil are increasing their emissions of greenhouse gases at a huge rate.

There is a risk that the good progress made by some countries might be overtaken by increased emissions by others.

At the same time, it’s difficult to expect developing countries to stop deforestation, if it means that they also have to stay relatively poor.

Some countries argue that while emissions by the West may reflect lifestyle choices, for some developing countries, they reflect people’s actions to survive.

Moreover, the countries that have contributed the least to climate change also stand to be the most affected by its effects.

The consequences of climate change in the developing world could include extensive flooding and food insecurity, conflicts over resources, harsher and more frequent natural disasters and large movements of climate refugees.

The main hope here is economic…

…For the richest countries to develop new, clean technologies and make them available to developing economies at low cost.

So that developing economies can grow and prosper, employing new, green technologies, without ever building the kind of fossil fuel infrastructure that the rest of the world is trying to unpick now.

To help developing economies avoid the extensive use of fossil fuels by using renewable energy instead.

And that financing by the West can help to fund and protect the ancient and precious forests of the world.

There is also hope in the hands of the people…

That through green education and lifestyle changes we develop a healthier relationship with the planet, which ultimately benefits both us and nature, and results in an improvement in our standard of living.

Do the first-movers in emission-reduction stand to lose out?

Climate change is a global problem. It will affect all countries across the globe, whether they have been producing emissions or not.

Regardless of who has produced what and when, we all stand to lose everything if no action is taken to reduce greenhouse gas emissions to net-zero.

At the same time, we know that economic development is closely linked with energy production.

The countries with the resources, worker skills and technology to develop low cost, low carbon solutions and spread them around the world stand not only to reduce their own emissions but to also gain economically.

The economics is firmly in their favour if they act now.

To avoid poorer countries from becoming fossil-fuel-dependent, we need low carbon technology to be cheap and available.

The cost of renewables is falling quickly, with a variety of new technologies being developed in many sectors.

But this process needs to speed up.

If the rich countries of the west were to decide to seriously tackle climate change, the rest of the world would follow.

Just like when the EU enforced energy efficiency standards for technology, the rest of the world adopted them too, because they wanted to continue trading with the block.

That would also give some of the slower moving economies some additional time to reduce their emissions and adopt the new, cleaner technologies.

What is net zero? and which countries have a net zero target?

The point at which we reach net zero greenhouse emissions is the point at which we halt the increase in global warming.

The chart below shows the countries that have set a net zero emissions target.

Carbon dioxide is stored in the atmosphere for around 200 years. So stopping the emissions of CO₂ today would not eradicate the existing greenhouse gases already in the atmosphere. These would continue to cause global temperatures to rise and climate change.

The immediate challenge is rather to stop greenhouse gases from becoming even more abundant.

If we continue to increase the amounts of CO₂ in the atmosphere, we continue to warm the planet faster.

We need to reach net-zero as soon as possible. To achieve that, everyone needs to do the most they can to reduce emissions.

Right now, we are not all doing that.

But we can begin today.

And if some countries drag their feet, others will have to lead the way.

What is the difference between net zero and carbon neutral?

Net zero means an exact balance between the amount of greenhouse gases being emitted into the atmosphere and the amount being drawn back down and taken out of the atmosphere.

Net zero includes taking actions to reduce carbon emissions to the lowest amount possible.

It can refer to the emissions generated globally, by a country, a company, even an individual good or service.

To understand this more clearly, take the example of a company manufacturing a range of goods that wants to reach net zero  

It first reduces the amount of greenhouse gas emissions it produces through all of its manufacturing processes to the lowest level possible.

Then for the emissions that are essential and can’t be avoided in the production processes, it uses something to remove the same amount of emissions from the atmosphere in a permanent manner.

This might include, for example, planting trees or using a new technological approach to draw down carbon dioxide from the atmosphere.

In summary, the company has reduced its greenhouse gas emissions as much as possible. The resulting amount of ‘essential’ emissions released is counterbalanced by the same amount being removed from the atmosphere.

You can say that the company has reached net zero carbon emissions.

Carbon neutral is a term that is similar to net zero.

It doesn’t mean the same thing, although it’s often mistakenly used that way.

While net-zero includes an element of actively decreasing emissions as much as possible, carbon-neutral doesn’t.

It just refers to a policy of not increasing carbon emissions. And of achieving carbon reductions through offsetting measures.

When the planet reaches net zero, the increase in carbon dioxide in the atmosphere will stop and the increase in global warming also stops.

Zero emissions or zero-carbon are different terms and mean that no emissions were produced.

How close are we to net zero emissions?

At COP21 (21st Conference of the Parties) in 2015, nearly every country in the world agreed to limit global warming to “well below” 2°C above pre-industrial levels and pursue efforts to limit it to 1.5°C.

To limit global warming to 1.5 degrees, we would need steep reductions in greenhouse gas emissions and faster progress towards net zero targets.

It would imply halving global greenhouse gases by about 2030 and reaching net zero emissions globally by about 2050.

The blue line on the chart below presents this path.

The red line gives the corresponding path for limiting global warming to 2 degrees.

While there has been a lot of rhetoric from countries and businesses about net zero emissions targets in recent years, we are still far away from the emission reductions needed to fulfil the Paris Agreement.

Most countries have agreed on the long-term goal of net zero emissions.

But at COP26 in 2021, the short-term commitments and concrete policies needed to achieve the emission reductions by 2030 on the 1.5-degree path were not yet put in place.

There also appeared little general willingness to set tough 2030 targets.

The bottom line is that the goal of keeping global warming below 1.5 has already passed.

But there are still some reasons to be optimistic:

• There is now a clear scientific consensus on the need to reach net zero emissions.
• A series of new ambitions, action pledges and net zero targets have been made.
• There is a general realization that the economic picture of tackling climate change and moving towards net-zero looks positive.
• With all the new pledges and net zero emissions targets added up, there is a path close to the red line that is in place.

While there has been much emphasis on decarbonizing, including an increased use of renewable energy, investment and finance need to follow.

To limit warming, all the pledges made to reduce greenhouse gases need to be delivered. The detailed policy steps for reaching net zero targets also need to be put in place.

The chart below shows the current status of the net zero emission targets achieved, in law, in policy, or as a pledge.

How can we draw down carbon dioxide from the atmosphere? What is a carbon sink? And a carbon budget? For the answers to these questions and more, read all about carbon and carbon sequestration.