Who contributed the most to global warming?

When we try to compare how countries, gases and industries contribute to climate change, we often compare emissions. We look at emissions per capita or at the share of a country or industry in the global pie. It is a very good indicator, but it does not directly measure the impact on the climate.
A new paper by Matthew Jones and the Global Carbon Project team has quantified how much countries have contributed to the increase in global average surface temperature since 1851. I dug through the data and picked out a few key takeaways. I've also made them available in our data explorer on Our World in Data if you want to explore them yourself.
Let's take a look at it.
Only two-thirds of the current warming comes from CO2 emissions. Before we get into the contributions of individual countries, let's look at how much warming different gases have caused. When climate change is mentioned, most people think of carbon dioxide (CO2). They hypothesize that it is responsible for most of the global warming. However, other greenhouse gases – methane and nitrous oxide – also played a big role. I have shown in the graph how much each of them contributed to the warming from 1851 to 2021. CO2 contributed the most - 1.1 °C, which is a little over two-thirds of the warming. Methane contributed 0.4 °C, which is one quarter of the warming.2 And nitrous oxide represents 5 %. You may have noticed that this adds up to 1.6°C. This is already more than the global goal of 1.5 °C! This is because these data do not include the cooling effects of sulfur dioxide and aerosols. If we include them, the net change in global average surface temperature is about 1.1°C. That's the number we're used to hearing.
CO2 emissions from fossil fuels are increasingly dominant. We looked at a static view of how much warming each gas and source has caused so far. However, it is interesting to see how these contributions have changed over time. In the graph, we can see the share of individual gases and sources in warming in individual years. In 1851, most of the warming was due to land use change. Countries were cutting down forests, expanding farmland, and raising livestock that emitted methane. Only a few countries used fossil fuels to a significant extent. However, over the course of the last century we have seen fossil fuels take over. Their contribution to warming has steadily increased until today, when they are the largest contributor. If you want to see this breakdown by country, you can view it in our interactive chart.