Six key takeaways from the IPCC’s new climate report

Scientists have issued a ‘code red’ for humanity.

Eight years after its last update, the United Nations’ Intergovernmental Panel on Climate Change (IPCC) has published its latest report on the state of the global climate. At nearly 4,000 pages long and involving more than 200 scientific authors, the comprehensive report makes clear how profoundly humans have altered the climate, and what will happen if we continue on our current trajectory.

In a statement, United Nations Secretary General Antonio Guterres said – in what is the IPCC’s strongest wording yet – that the report represents a “code red for humanity”, stressing that “global heating is affecting every region on Earth, with many of the changes becoming irreversible”.

Here are the report’s key takeaways.

1.  Climate change is definitely man-made

In its last report, the IPCC said the link between human activity and climate change was “clear”, now it’s gone a step further, stating that it is “unequivocal that human influence has warmed the atmosphere, ocean and land”. Researchers have found that the temperature of the planet has risen as the volume of man-made carbon dioxide (CO2) and methane in the atmosphere has increased, in a way that would not have occurred naturally.

2.  Climate change is happening at an unprecedented rate

The current rate of warming has not been seen in Earth’s preceding 100,000 years, and the decades since 1850 are “unprecedented”. While it’s true that global temperatures have gone up and down during those 100 millennia, at no point has it ever been as warm as it is now. The authors say that if only natural drivers of temperature changes had been active within the last 170 years, the planet would be roughly the same temperature as it was in pre-industrial times.

3.  We’re on the cusp of the 1.5C threshold

Society’s reliance on fossil fuels means the planet has already warmed 1.2C. The report’s projections indicate we’re “more likely than not” to reach or exceed 1.5C within the next decade or two – this is the threshold scientists say it is critical to stay below if we’re to avoid the worst consequences of climate change.

4.  Scientists can now link specific weather events to man-made climate change

As recently as 20 years ago it was almost impossible to attribute a particular weather event – such as a storm or heatwave – to climate change, but that’s no longer the case. Since the IPCC’s last major report in 2013, scientific methods have matured to the point where indisputable links between the two can be made – and quickly. In the wake of the deadly heatwave that engulfed North America in June researchers needed just days to ascertain that the occurrence would be “virtually impossible” without climate change.

5.  Some effects of climate change will be irreversible

Even under the lowest emissions scenarios, warming that has already occurred has triggered changes that will persist long into the future. Ice sheets will continue to melt for hundreds to thousands of years, according to the report, prompting sea levels to rise well beyond 2100. Even if warming is kept below 2C, sea levels are expected to rise around three metres by 2300. And with so much CO2 already in the atmosphere, the IPCC predicts that – even if we were to halt emissions immediately – warming will continue for several years to come.

6.  All is not lost

The report makes for sobering reading, but scientists broke new ground in this edition by projecting what will happen when global emissions get to zero. While it seems unlikely we’ll be able to avoid a global temperature rise of 1.5C, we can avoid an increase of 2C if we take aggressive action now.

Also for the first time, the report provides a more detailed regional assessment of climate change, including a focus on useful information that can inform risk assessment, adaptation, and other decision-making, and a new framework that helps translate physical changes in the climate – heat, cold, rain, drought, snow, wind, coastal flooding, and more – into what they mean for society and ecosystems.

Finally, the authors note, “every bit of warming matters”, so every action we take to reduce greenhouse emissions – on every level – will make a difference.

The bottom line

The IPCC report paints a very bleak picture for the future of the planet, but it’s not yet too late to turn the tide. This report must act as a wake-up call for people, governments and corporations everywhere. Aggressive action is needed immediately if we’re to save our one home.

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