Q&A: What is the IPCC report and what needs to be done to address the climate crisis?

Synthesis report analyses almost 10 years of climate science and most likely scenarios facing the world this century

The Halemba coal mine in Rybnik, Poland: Without 'deep rapid and sustained greenhouse gas reductions', we will shoot past a 1.5 or 2 degree temperature increase by mid-century, the IPCC report warns. Photograph: Bartek Sadowski/Bloomberg
The Halemba coal mine in Rybnik, Poland: Without 'deep rapid and sustained greenhouse gas reductions', we will shoot past a 1.5 or 2 degree temperature increase by mid-century, the IPCC report warns. Photograph: Bartek Sadowski/Bloomberg

The world has reached a critical point. What it needs now, according to the Intergovernmental Panel on Climate Change (IPCC), is to urgently address an “actions deficit” when it comes to facing down the consequences of an overheating planet that is affecting everyone, everywhere.

This is the overriding conclusion of the world’s leading climate scientists in their latest global review.

In short, they say that without critical actions in the form of “deep rapid and sustained greenhouse gas reductions”, we will shoot past a 1.5 degree temperature increase – and possibly even 2 degrees – by mid-century.

Yet, we still have the time and we know what actions work. There is no need for magical solutions over the coming decades – a cause for hope, rather than despair. The solution is cheaper than the problem. We can stabilise the world at about 1.5 degrees with swift action to drive down global emissions, its report affirms.

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The scientists reveal the sheer scale of ambition required to avoid the worst consequences of climate change, while facing up to realities, such as “the world now is the coolest it is going to be, at least for many decades”.

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Without immediate and equitable mitigation and adaptation, the climate crisis increasingly threatens societies and human wellbeing, especially climate-vulnerable countries in the Global South. But the report also shows the range of currently available and cost-effective ways of cutting emissions and building climate resilience.

Renewed efforts to invest in sustainable development give us the best chance of a climate-resilient future, the pot of money to do so is overflowing. Failure to do this will have consequences for thousands of years.

What exactly is the IPCC synthesis report?

It’s the final instalment of the sixth global assessment report (AR6) by the IPCC, the UN body of leading climate scientists.

It lays bare the devastating reality and risks posed by the climate crisis, and sets out ways in which the world should respond. It is called the synthesis report as it draws together findings of the preceding three main elements, known as working group reports. These add up to a definitive review of global knowledge on the climate crisis.

They covered the physical science of the climate crisis; the already happening impacts of the climate crisis (and how to adapt to them); and ways of reducing carbon emissions.

The latest report also takes into account three other IPCC reports published since 2018 on impacts of global heating of more than 1.5 degrees; land use; and on oceans and the cryosphere (ice caps and glaciers).

What are the key findings?

While there is no new science in the report, it packs a punch. It strongly echoes warnings that the world is approaching “irreversible” levels of global heating with catastrophic impacts becoming inevitable, much of which will arise from more frequent extreme weather events.

Drastic action is needed to avoid disaster in multiple guises. Yet, it is not a doomsday document. Much of it sets out policies and actions likely to stave off the worst ravages of climate breakdown.

Unfortunately, however, it confirms the world is in the throes of “a human-induced polycrisis” driven by interlinked issues of global warming, loss of nature, overreliance on fossil fuels (threatening energy security and price volatility) and worsening water shortages.

We are misusing water, polluting it and changing the whole global hydrological cycle, through what we are doing to the climate, a separate UN report found this month.

And there is a gross inequity problem. Ten per cent of high emitting households are responsible for 40 per cent of global emissions. This strongly correlates with wealth, with most in the developed world. The bottom 50 per cent are responsible for just 13-15 per cent of emissions.

What was the purpose of this report?

It seeks to reduce 10,000 pages of science to a shorter format, including a “summary for policymakers”, to provide scientific underpinning for global climate action, especially over the pivotal coming decade.

It is written by scientists primarily, though haggled over by representatives of the UN’s nearly 200 member governments who were signatories to the 2015 Paris Agreement. The evidence it sets out is indisputable.

It will inform the next UN climate summit, Cop28, hosted by the United Arab Emirates in Dubai next November, where a global “stocktake” will be undertaken. This will evaluate progress since 2015 on key targets to cut emissions, notably “nationally determined contributions”. It will confirm governments are well off track.

Will this report change anything?

The IPCC is a much changed entity. Its work has seen off climate deniers, and is increasingly focused on how best to pursue decarbonisation and what works in making a climate-resilient world based on what the science says.

Previous AR6 reports showed the current 1.1 degrees of warming has already caused dangerous disruption to nature and human wellbeing across the world, with many climate impacts worse than predicted in the 2014 synthesis report.

In 2018, it warned emissions must be halved by 2030, compared with 2010, to have a good chance of limiting temperature rises to 1.5 degrees. Yet emissions continue to climb to the highest level in human history. Last year’s increase is probably due to the energy crisis and a reliance on fossil fuel use.

Working Group III findings revealed that despite some positive policy initiatives, we are way off track to limit warming to below catastrophic levels.

In short, the synthesis report confirms an alarming ambition gap as current policy and financial pledges to 2030 make it impossible to limit warming to 1.5 degrees. And the limits of adaptation – essentially how we can become climate resilient – are already being reached.

That leaves a rapidly diminishing “carbon budget” for the world to stay within the IPCC’s advised limits. We are in “code red” territory with CO2 concentration at its highest level in two million years and sea levels rising at their fastest rate in 3,000 years.

All told, it’s the scientific basis for effective climate action and the means to help spur governments to implement immediate measures to phase out fossil fuels, slash emissions across all sectors and to restore nature – described as climate’s secret ally.

What are we to make of the synthesis report?

The bleakest summary might read: It’s getting worse and we’re heading to 3 degrees of warming or more this century. Yet, there are options with transformative action and forcing down emissions will bring progress relatively quickly.

The case for banning new oil, gas and coal immediately and for much faster scaling up of renewables and electrification is incontrovertible. It is fair to say that view would be endorsed by most scientists, not to mention a great many energy experts and macroeconomic analysts.

Reaching net-zero emissions in a cost-effective manner remains the big challenge, but it is achievable.

It may also be necessary to develop technologies that suck carbon dioxide from the air, called “direct air capture”, or to explore other means of “climate repair” but such options are unproven and cannot be banked on yet. So we should concentrate on known solutions.

What should be the priority now?

The most worrying aspect is that there are big commitments and ambitious targets, but insufficient action to date.

Saul Griffith, in his book Electrify – An Optimist’s Playbook for our Clean Energy Future, notes “all too many people in climate advocacy are beginning with the question of ‘what is politically possible?’”

That could be a result of frustration that drives many people, including our children, to march and protest for more rigorous climate action, he observes. “But aiming only for what is politically possible is the art of limiting ambition before you begin.”

The first question should be: “What is technically necessary to reach a climate solution that is also a great economic pathway for a country?”

Author Eoghan Daltun explains how rewilding his parcel of land in Cork allowed it to become Ireland's most ecologically diverse temperate rainforest.

What should governments do?

Reduce emissions sharply and give up fossil fuels, through investments in renewable energy and other low-carbon technologies, increase energy efficiency, rethink agriculture and restore forests and degraded natural landscapes. And in electrifying almost everything, recognise that there is a need for a flexible grid system and radical reform of energy markets.

Not easy. But, above all, they need to build trust by providing reassurance that this is the pathway to success. There will be necessary pain but this can be minimised by a genuine just transition.