It's crunch time in our fight against climate change. If we act now to reduce greenhouse gas emissions, we can keep our planet safe for future generations. That's the message of hope contained in a major scientific report released by the United Nations' chief climate science organization on Monday.

On the flip side, if we don't act to reduce greenhouse gas emissions across all sectors, we will fail to limit global warming to the critical temperature change of 1.5 degrees Celsius, according to the scientists on the Intergovernmental Panel on Climate Change, or IPCC. Right now, the necessary actions aren't being taken, said the report, which UN Secretary General António Guterres described as "a litany of broken climate promises" and "a file of shame."

"We are on a fast track to climate disaster," he said during a press conference, pointing to the terrifying storms, widespread water shortages and extinction of millions of species of plants and animals that will result from us refusing to change our ways. "This is not fiction or exaggeration, it is what science tells us we will result from our current energy policies."

But Monday's IPCC report does offer us cause for optimism. If governments, businesses and individuals follow the advice laid out by scientists, we could avert disaster and also improve living standards around the world, with a minimal knock-on effect on global GDP.

Titled Climate Change 2022: Mitigation of climate change, the report was approved on April 4 after being ratified by the 195 member governments of the IPCC. It contains the landmark findings on solutions to reduce global warming assembled by 278 scientists from 65 countries. These include options across all different sectors that have the potential to halve emissions by 2030, while fueling sustainable development and leading to the creation of a more equitable and just society.

Monday's report is the final installment in a trio of key publications from the IPCC, which also includes the The Physical Science Basis report, released in August, and the Impacts, Adaptation and Vulnerability report, which was published last month. Together, these reports present a robust analysis of the latest climate science, the impacts of global warming and potential solutions.

In the first IPCC report, we learned that the Earth is already beginning to feel the irreversible impacts of climate change as global warming has hit 1.1 degrees Celsius. Last month's report, which Guterres called "an atlas of human suffering," showed how people around the world were being "clobbered" by these impacts. But this latest report offers us hope that we can mitigate some of the effects of the climate crisis – if we act now.

"We are at a crossroads," said IPCC Chair Hoesung Lee. "The decisions we make now can secure a liveable future. We have the tools and know-how required to limit warming."

Lee added that he felt "encouraged" by the action being taken around the world to limit global warming. Now the solutions being used to reduce emissions need to be scaled up and applied more widely to support deep reductions and further innovation, he said. And this needs to happen within the next decade. 

Now or never

The urgency of putting mitigation efforts in place is based on projected global warming figures.

Limiting global warming to either 1.5 degrees and 2 degrees is enshrined in the Paris Agreement for good reason. As the planet continues to warm, even to this seemingly small extent, the impacts on our environment, including frequent extreme weather events, will increase exponentially. This, in turn, will lead to further impacts on humans, including widespread poverty, famine and mass migration.

Last decade, average annual global greenhouse gas emissions reached their highest levels in human history, and the report makes it clear we can't go on this way. The rate of growth since 2019 has already slowed, but that growth will need to stop all together in the next three years.

If we want to limit global warming to just 1.5 degrees or 2 degrees Celsius, global greenhouse gas emissions will need to peak before 2025 at the latest. They'll then need to be reduced by 43% by 2030 to keep to 1.5 degrees of warming. Even if we manage to do this, it's likely we'll see the 1.5-degree threshold exceeded – but this might only be temporary. Global warming could return to below 1.5 degrees by the end of this century. Methane also needs to be reduced by one third by 2030.

"It's now or never, if we want to limit global warming to 1.5°C," said IPCC Working Group III Co-Chair Jim Skea. "Without immediate and deep emissions reductions across all sectors, it will be impossible."

Solutions to save the planet

The report lays out mitigation strategies that span sectors including energy, urban, transport, buildings, industry, and agriculture and forestry. There are enough solutions to at least halve emissions across all these different sectors by 2030 – if those solutions are acted upon.

Change needs to take place across the board, but it's the energy sector that will have the most impact across all other sectors. Fundamental transformation will need to involve a substantial reduction in fossil fuel use, widespread electrification, improved energy efficiency and use of alternative fuels (such as hydrogen). The report concluded that coal must be phased out, and that new plans for new fossil fuel infrastructure would need to be scrapped to avoid crossing the 1.5-degree threshold.

Fortunately, as the report highlights, there has been a massive decrease of up to 85% in the cost of key technologies such as solar, wind and batteries for electric vehicles since 2010, which makes the ongoing transition within the energy sector far more affordable.

"We must triple the speed of the shift to renewable energy and that means moving investments in subsidies from fossil fuels to renewables," said Guterres. "It's time to stop burning our planet and start investing in abundant renewable energy all around us."

Coming up next

Now that all three IPCC reports have been released, a final synthesis report, which comprises the analysis of all three working groups and three special reports, will be published in September, compiling all the research from the AR6 cycle.

Publication will occur just before the major climate change conference COP27 takes place in Egypt.