Human emissions of carbon dioxide and other greenhouse gases are the primary drivers of the global rise in temperatures.¹ This link between global temperatures and greenhouse gas concentrations – especially CO₂ – has been true throughout Earth’s history.²

In the chart, we see the global average temperature relative to a baseline, which is the average between 1961 and 1990. Average temperatures have risen by over 0.8°C since then.

You can also see that temperatures in 1850 were around 0.4°C cooler than the baseline, giving us a total temperature rise of about 1.2°C compared to pre-industrial times.

This warming has not been equally distributed across the world. The Northern Hemisphere has warmed more than the Southern Hemisphere. And warming has been especially strong at the poles. In some regions, temperatures have risen by more than 5°C. You can see this distribution in maps published by Berkeley Earth.

Human emissions have been the main driver of this change. Aerosols have played a slight cooling role in global climate, and natural variability has played a minor role. This article from Carbon Brief explains this very well, with interactive graphics showing the relative contributions of different factors on the climate.

If we want to stabilize (or even reduce) concentrations of CO₂ in the atmosphere, the world needs to reach net-zero emissions. This means our net carbon contributions to the atmosphere are zero: any remaining emissions are offset by carbon sinks. This requires significant reductions in emissions.

However, emissions from fossil fuels have not yet peaked.

In the chart, you can see global CO₂ emissions since 1750, broken down by world region. Emissions have increased rapidly over the last half-century.

While this growth rate has slowed recently, fossil emissions are still rising.

Current policies to reduce, or at least slow down, the growth of CO₂ emissions have already averted some future warming compared to a world without these policies.

As we see in the chart, climate and energy policies – which include adopted and implemented policies (such as legislative decisions and executive orders) would reduce warming relative to a world with no climate policies.

This chart maps out future greenhouse gas emissions scenarios under a range of assumptions: if no climate policies were implemented; if current policies continued; if all countries achieved their current future pledges for emissions reductions; and the necessary pathways compatible with limiting warming to 1.5°C or 2°C of warming this century.⁴

Current policies have us on track for around 2.7°C by 2100.

And if countries achieved their current pledges, this could be reduced to 2.1°C.

But if we aim to limit warming to “well below 2°C” – as is laid out in the Paris Agreement – currently policies have us far off track. To achieve this goal, countries need to increase the ambition of these commitments and bring their policies in line with them.

There is no single metric that captures the distribution of CO₂ emissions across the world, today or in the past.

We can compare the total emissions of countries every year. But this fails to take population size into account; you’d expect a country with more people to have higher emissions. Even then, comparisons of total or per capita emissions today don’t capture historical contributions. Some countries that now have relatively low emissions have had high emissions for centuries.

These metrics tell us different things. We make all of them available by country in our data explorer.

In the chart, we see one metric to compare across the world: emissions per person. There are massive differences in emissions across the globe. Some of the wealthiest countries emit 100 times more per person than the poorest.

Read more:

Per capita, national, historical: how do countries compare on CO2 metrics?

There are many ways to measure countries’ contributions to climate change. What do they tell us?

Global emissions are still rising, but many countries have managed to reduce their emissions in recent decades.

Domestic emissions in the UK have roughly halved since 1970. Emissions in the European Union have fallen by more than one-quarter.

Part of this is because many rich countries have ‘offshored’ some of their emissions by importing CO₂-intensive goods manufactured elsewhere – but we still see a significant decline in emissions after adjusting for trade. Consumption-based CO2 emissions have declined very substantially in many countries.

Many of these countries have grown their economies at the same time: GDP per capita has increased while consumption-based emissions have fallen. The chart shows the data for various countries that have achieved this decoupling.

Read more:

How do CO2 emissions compare when we adjust for trade?

Which countries are net importers and exports of emissions? How much CO2 is ‘offshored’?

Many countries have decoupled economic growth from CO2 emissions, even if we take offshored production into account

It is possible to reduce emissions while growing the economy. But this decoupling needs to happen faster.