Global surface temperature has already increased by 1.09°C since pre-industrial times – faster than at any point in at least the last 2000 years.
The Intergovernmental Panel on Climate Change (IPCC) is the United Nations body for assessing the science related to climate change.
In 2021 and 2022, the IPCC released three reports from its sixth assessment cycle (AR6) covering the latest science on the physical state of the global climate, the impact of climate change and mitigation of climate change.
Climate change is happening all around us
Fingerprints of this rapid climate change can be found in the atmosphere, ocean, cryosphere and biosphere, from retreating glaciers to rising sea levels.
Drought
Human influence has unequivocally warmed the atmosphere, ocean and land
410
PPM C02
1,866
PPB CH4
Burning fossil fuels, changes in land use and forestry, and industrial processes have caused greenhouse gas levels in the atmosphere to increase dramatically.
Carbon dioxide (CO2) levels have increased by 47.3% and reached annual averages of 410 parts per million. Methane (CH4) is at 1,866 parts per billion, up by 157.8%.
Of these activities, reliance on fossil fuels is the root cause of climate change: in 2019, coal, oil and gas contributed to 80% of all human-related CO2 emissions.
Climate change is an unequivocal threat: it is already causing irreversible damage to our well-being and planetary health.
Extreme weather events such as heat waves and floods have become more frequent and intense, bringing increasingly irreversible losses.
Thanks to climate attribution science, we know these are linked to human-induced climate change.
These impacts of climate change will increasingly occur at the same time, interacting with each other as well as other risks – leading to more and more dangerous consequences.
Further warming will increase losses and damages from climate change, often beyond our – and our planet’s – ability to adapt.
If temperature rise passes 1.5°C, entire ecosystems in the polar, coastal and mountain regions will be forever lost. Even at 1.5°C of warming, from 3% to 14% of all terrestrial species will face a very high risk of extinction, and further warming will make these threats to biodiversity even worse.
Even a small amount of additional warming will threaten food production and food security, due to more severe and frequent heat waves, droughts and floods, along with sea-level rise.
More extreme weather and heat waves, as well as infectious diseases on the rise due to warming, will lead to more ill health and premature death.
If we want to find ourselves within the 1.5°C limit by the end of this century, we need to reduce emissions across all sectors, and fast.
Our best estimate based on historical data and climate models suggests that the world will reach the 1.5°C limit by 2030-2035, but that’s not the end of the story.
If we want to have at least a 50-50 chance to stay within that limit, the world can only afford to emit around 460 billion tonnes more of CO2; the equivalent of 11.5 years of annual emissions in 2020.
This means we can’t avoid some impacts of climate change, but we should still work as hard as possible to keep those to an absolute minimum.
We can achieve that by deep and rapid cuts in emissions of all major greenhouse gases, particularly CO2 and methane.
CO2 is the largest contributor to global warming. It stays in the atmosphere the longest – up to 200 years. The damage created by CO2 emissions is something we experience today, and will continue to experience for decades to come.
This is why scientists initially focused on lowering CO2 emissions. However, in the IPCC AR6 WGI and III reports, it was found that another greenhouse gas needs to be dealt with urgently: methane.
Methane lives for only a short time in the atmosphere – around 12 years. Yet, it is a very powerful greenhouse gas – about 80 times more potent than CO2 over a 20-year time horizon. There is now so much of it that it is forcing global warming even faster.
Reducing carbon and methane emissions is vital to meeting the Paris Agreement temperature targets.
There are some technologies, still in very early stages of development, which can help get us to net zero emissions by 2050. These are called carbon capture and storage (CCS) and carbon dioxide removal (CDR).
In theory, CCS should be added to the last bits of fossil fuel infrastructure that we can’t transition away from.
While CDR can help to balance or ‘restore’ the atmospheric greenhouse gas levels by taking carbon out of the atmosphere, therefore removing the main driver of warming.
Such technologies require a significant amount of money and research, and even though capturing or removing carbon can work, it’s not a ‘get out of jail free’ card – we need to reduce emissions now.
Yet, governments are treating these technologies like a licence to keep growing fossil fuel use, despite the IPCC AR6 WG3 report being clear that there is no room for new fossil fuels in a Paris-aligned world.
So, where does that leave us?
The window of opportunity for a liveable future for all is closing fast.
We cannot afford further delay in transitioning to clean, renewable energy and slashing emissions.
Not all countries and people have contributed equally to the current state of the climate, and even now up to 45% of global greenhouse gas emissions come from the richest 10% of households around the world.
Our best estimate based on historical data and climate models suggests that the world will reach the 1.5°C limit by 2030-2035, but that’s not the end of the story.
To keep warming to 1.5°C until the end of the century, we need to start reducing global emissions no later than 2025 and reach net zero by mid-century.