What can we expect from the final UN climate report? And what exactly is the IPCC?

After all the talk about the need for climate action, it’s time for a reality check. The world will receive the latest climate report from the United Nations on Monday. And it’s a big one.

Hundreds of scientists, who form the so-called Intergovernmental Panel on Climate Change (IPCC), have been working hard behind the scenes. They’ve produced a series of reports in the latest round, which started in 2015. But on Monday, it all comes together in what’s called the Synthesis Report.

It will explain how greenhouse gas emissions are warming the planet and then address the consequences. There is attention to where we are most vulnerable, as well as efforts to adapt. And then, how we act to reduce emissions and mitigate climate change.

Gathering all the evidence, from every corner of the world, is a huge undertaking, let alone reviewing the science to reach consensus. It is a process that has repeated itself several times since its inception more than three decades ago.

This is the sixth reporting round. And it won’t be the last. But this is a critical moment as the opportunity to limit warming and avert dangerous climate change is slipping away.

What is the IPCC and why do we need it?

The IPCC consists of 195 member states charged with producing comprehensive and objective assessments of the scientific evidence for climate change.

The World Economic Forum ranks the failure of climate action as the biggest risk on a global scale in the next decade. And several other top ten global risks – extreme weather, biodiversity loss, damage to the human environment and natural resource crises – are exacerbated by climate change.

Governments, industries and communities are becoming increasingly aware of the need to address climate change, especially as predictions become reality.

The scientific effort to understand the causes, effects and solutions is enormous and increasing. Tens of thousands of new peer-reviewed scientific studies on climate change are published each year. There must be a way to identify key messages in this vast body of scientific evidence and use this information to make better decisions. This is what IPCC reports do.

The IPCC process also provides a framework for the scientific community to organize and coordinate their efforts. Each reporting cycle is linked to an international scientific effort, conducting standardized experiments to test the reliability of current climate models.

The experiments include multiple possible scenarios for how greenhouse gas concentrations in the atmosphere could change in the future, depending on choices made today. The range of results produced by different models in these sets of experiments helps determine how much confidence we have in the impacts of climate change expected in the future.

An important aspect of IPCC reports is that they are produced in collaboration with scientists and governments. The summary of each report is negotiated and approved line by line, with consensus from all IPCC member governments. This process ensures that the reports remain true to the underlying scientific evidence, but also contain the most important information that governments need.

What can we expect from Monday’s report?

The synthesis report will draw from all six reports released in the current cycle.

They include three so-called “working group reports” on:

• the scientific basis of climate change

• effects, adaptation and vulnerability

• softening.

In addition, there were three special reports that cut across these working groups and dealt with specific topics, with governments asking for rapid assessments to help them make decisions. They related to:

The key statements of this cycle of IPCC reports are clearer than ever. They leave absolutely no room for disputing man-made warming and the need for urgent reductions in greenhouse gas emissions this decade. We can expect similar strong and clear headlines from Monday’s report.

How have IPCC reports changed?

Looking back at IPCC reports over the past 33 years shows how our understanding of climate change has improved. The first report in 1990 stated “the unequivocal detection of the enhanced greenhouse effect from observations is unlikely for more than a decade.” Fast forward to 2021 and the equivalent assessment now states, “It is unequivocal that human influence has warmed the atmosphere, ocean and land.”

In some cases, the pace of change has dramatically exceeded expectations. In 1990, West Antarctica was an area of ​​concern, but it is not expected to lose large amounts of ice over the next century. But by 2019, our observations show that glaciers in West Antarctica are rapidly retreating. This has contributed to an accelerated rise in sea levels worldwide.

There are also new concerns about the stability of parts of the East Antarctic ice sheet once thought to be protected from human-induced climate warming.

This shows the tendency for IPCC assessments to underestimate the scientific evidence. Climate science is often accused of being alarmist, especially by those who try to delay action on climate change, but in fact the opposite is true.

The production of IPCC reports based on consensus with governments means that statements made in the report summaries are justified by multiple scientific evidence. This may fall short of current discoveries of climate science.

What’s next?

Plans are already underway for the IPCC’s next review cycle, which is due to start in July this year. It is hoped that the next set of reports will be produced in time to inform the Global Stocktake in 2028, where progress towards the Paris Agreement will be assessed.

The current cycle (sixth assessment) has been grueling. Scientists have stepped up their efforts to work with governments to provide the clear and robust information required.

Writing and approving reports in the midst of a global pandemic compounded the challenges. This also applied to the inclusion of three special reports in addition to the usual three working group reports.

The evidence for human-induced climate change is now unequivocal. This has led to calls for future IPCC reports to more efficiently assess fast-changing fields of science and cut across working groups. This would bring together assessments of causes, impacts and solutions to key aspects of climate change in one report, rather than always splitting them into separate working group reports.

The establishment of the IPCC signaled that climate change was a major global issue. Despite this recognition more than three decades ago and the increasingly worrying reports from the IPCC today, global greenhouse gas emissions have continued to rise year after year.

However, there is some hope that we are approaching the peak of global emissions. By the time the next IPCC reports are released, global climate action may have finally begun to put the world on a more sustainable path.

Time will tell. Let’s hope policymakers are on the right side of history with the science.

This article is republished from The Conversation under a Creative Commons license. Read the original article.