As world leaders gather in Brazil for the UN's annual climate conference, the heat is on to find solutions to the rising global temperatures wreaking havoc across the world.  

Thirty years since the first COP event in Berlin sounded the climate alarm, emissions are reaching new highs. Here's the breakdown of how much global warming has already changed the planet. 

#1 Which regions emit the most CO2?

Governments are increasingly pledging to move toward net-zero or carbon neutral economies by 2050, meaning they aim to balance the greenhouse gases they produce with the ones they remove from the atmosphere. With emissions stabilizing in Europe and the Americas, and rising in Asia and Africa, this chart shows there's still a long way to go to decarbonize economies. 

But absolute emissions only tell half of the story. Populations in Asian countries have soared over the last decades. More people means greater consumption of resources. 

The picture transforms when seen from a CO2 per capita perspective. Factoring in population size puts a greater spotlight on both Western countries like the US and Australia, as well as nations in other parts of the world, including Saudi Arabia, Oman, United Arab Emirates, the US and Canada. 

Experts argue wealthy countries — particularly those who have historically contributed the most to global CO2 levels — have a greater responsibility to cut emissions.  

The infographic below shows average emissions per capita are higher for wealthier countries, although there are big variations within each income group.   

Global top-emitter Qatar spews out much more CO2 per capita than countries like Germany and France, although they are in the same income group. This suggests that wealth can be decoupled from emissions. 

And although countries like India and China rank low on per capita emissions, their decisions still have a big impact, given their huge population numbers (bubble size). 

#2 What are the major sources of greenhouse gas emissions?

At 29%, the power sector, which generates and delivers energy that drives our lives and economies, accounts for the greatest source of greenhouse gas (GHG) emissions. 

Next up is the industrial sector, which produces the goods we use every day. It is responsible for (22%) of overall greenhouse gases — including CO2, methane and nitrous oxide — released into the atmosphere. 

Forests are vital for climate stability. They are known as "carbon sinks" for their ability to absorb huge amounts of CO2 from our atmosphere, which is stored in their trees and soil. This is then released into the atmosphere when they are cut, burned, or degraded. 

Over the last two decades, the annual amount of tree cover lost has gradually increased. Russia, Brazil and Canada were the world's biggest drivers of deforestation in 2024.

 

#3 How have CO2 emissions developed over the last centuries?

CO2 emissions from burning fossil fuels have been rising steadily since the early days of the Industrial Revolution. At first, as humans produced higher levels of carbon dioxide, Earth absorbed it in natural "carbon sinks," such as forests and oceans. 

But as humanity began to produce more CO2 and other greenhouse gases than the planet's ecosystems could naturally soak up, more of those emissions became trapped in the atmosphere. This is shown in the red area below. 

#4 How much has the world warmed already?

As CO2 concentrations increase, they trap heat from the sun in the atmosphere, causing the planet to warm like in a greenhouse.   

Compared to the 20th century average, the global temperature had increased by almost 1.3 degree Celsius (2.3 degrees Fahrenheit) in 2024. 

This change is measured by calculating the difference between temperatures observed at a specific time and place and the historical average for that same spot.  

The 1.3-degree Celsius increase in temperature is the global average of those variations. The difference can be much greater on a local level or for individual months. For example, September 2025 was almost 2 degrees Celsius warmer than September 1956. 

These rising temperatures are already making events, such as deadly heat waves, dangerous storms, and droughts that devastate harvests more intense and frequent. And conditions will only worsen if temperatures continue to rise.  

A rise in sea levels is among the most noticeable impacts of global warming. Higher temperatures melt ice caps and glaciers, increasing the total volume of water in the oceans. 

#5 How much sea level rise do we already have?

Sea levels have risen nearly 25 centimeters (9.8 inches) in the last 140 years, according to data compiled by the Commonwealth Scientific and Industrial Research Organisation (CSIRO), the Australian government scientific research agency. Around a third of that increase occurred in the last quarter of a century. 

Sea levels are rising worldwide. But the trend is most pronounced in the Arctic, which is heating faster than everywhere else. 

At the same time, the world's oceans are heating up. Water expands as it warms, contributing to rising sea levels.  

While sea levels are rising in most parts of the world and are higher than at other times in history, the changes aren't the same everywhere. This is due to Earth's uneven gravity field as well as ocean dynamics such as wind, heat, and evaporation. 

In some places, such as western Canada and northern Chile, tide gauges show steady or even receding seas. But in other regions, like islands in the southern Pacific and Indian Oceans, sea levels are climbing at an alarming rate. For these low-lying islands, the risk is so severe that some could disappear beneath the waves. 

Edited by: Anke Rasper, Tamsin Walker and Jennifer Collins.

This is an updated version of an article originally published during COP26 in 2021.