海角大神

A new science report from the United Nations will spell out in excruciating detail the pain of climate change to people and the planet with the idea 鈥� the hope really 鈥� that if leaders pay attention, some of the worst can be avoided or lessened.

One scientist calls it the 鈥淵our House is On Fire鈥� report.

While these reports often can come across as depressing, to scientists and world leaders, the idea isn鈥檛 to lower people鈥檚 spirits. The reports are designed to help the world navigate a dangerous future, back away from some cliffs where harms are irreversible and severe, and mostly to give leaders negotiating deals on how to curb future warming a sense of what can be done and why scientists say something must be done.

It鈥檚 really about hope not doom, said Robert Habeck, German vice chancellor and minister for economy and climate. American climate scientist Katharine Hayhoe of The Nature Conservancy and Texas Tech agreed.

鈥淗ope can lead to action,鈥� Mr. Habeck said in an interview with The Associated Press. 鈥淚f you鈥檙e afraid of something, then you hide away, you shy away, you run away. If you hope for something, then you can find some motivation, power, and energy in yourself. And this is what we need: hope that we can achieve great things that the problems of the moment can be overcome by building up a new renewable world.鈥�

What is in the report?

Monday鈥檚 report is from the Intergovernmental Panel on Climate Change (IPCC), a heavy hitter group of hundreds of scientists the United Nations asks to issue major reports every five to seven years about climate change. The scientists do three main reports. The first, on what鈥檚 known about the science behind climate change and general projections of future warming, came out last August and got nicknamed 鈥渃ode red鈥� by UN Secretary General Antonio Guterres. After Monday鈥檚 report, the second, a third report comes out in several weeks. It will be on options to confront climate change.

Monday鈥檚 report is about the impacts, what climate change has done, is doing, and will do to people and the world we live in. Ms. Hayhoe said if she were to give this report a nickname like the last one it would be: 鈥淵our House Is On Fire.鈥�

鈥淚t is a massive compendium of how climate change is affecting us here, now, in ways that matter to our lives,鈥� Ms. Hayhoe said in an email. 鈥淚t shows how we can and must prepare for the impacts we can no longer avoid.鈥�

And that means giving bad news about heat waves, floods, wildfires, droughts, sea level rise, disease, extinctions, and climate homelessness.

鈥淚t鈥檚 important for people to be honest about the amount of impacts we鈥檙e likely to see,鈥� said Stanford University environmental scientist Chris Field, who chaired this report in previous years.

How will the report be used?聽

鈥淪cience itself does not yet trigger actions,鈥� United Nations Development Program chief Achim Steiner said. 鈥淲e then have to respond. And the response to climate change today essentially affects every aspect of our lives.鈥�

Each year, leaders and diplomats from around the world meet to ratchet up efforts to curb climate change, resulting in several agreements, the last two being the Paris accord of 2015 and a pact in Glasgow last year. The IPCC reports are frequently mentioned in negotiations. Scientists, such as Ms. Hayhoe, attend to explain consequences.

Up until 2015, the world鈥檚 goal was to limit warming to 2 degrees Celsius (3.6 degrees Fahrenheit) over pre-industrial times. But during the negotiations for the Paris agreement, leaders of small island nations complained that 2 degrees of warming would make some of their islands, their countries, uninhabitable. So the Paris accord adopted a secondary, tighter, goal of 1.5 degrees (2.7 degrees Fahrenheit) and asked the IPCC to study what the difference would be between the two warming thresholds.

A 2018 special report from the IPCC found dramatic differences, including loss of coral reefs, sea ice, and some irreversible harms at 2 degrees that might not happen at 1.5 degrees. Making matters more immediate was the fact that the world has warmed 1.1 degrees since pre-industrial times, so this is about warming of just a few tenths of a degree from now.

鈥淭he fact is that it is the IPCC report of 2018 that refocused our energies from well below 2掳C to 1.5 degrees specifically ... as we did quite visibly and powerfully in Glasgow,鈥� United States special climate envoy John Kerry told The Associated Press in an interview. 鈥淎nd even China, Russia, India, other countries that may have some differences about the pace and rate and implementation of some of the climate initiatives, even they accepted that this was the standard now, the 1.5 degrees. So the IPCC has a profound impact.鈥�

鈥淎nd I anticipate that this report will, just like the prior ones, have a very significant impact on the climate debate,鈥� Mr. Kerry said. 鈥淚 think it鈥檚 going to be quite dramatic in the picture it paints of how far behind we are.鈥�

What time frame does the report look at?

These reports always look at what鈥檚 already happened in terms of climate change, what is happening now, and give projections on what鈥檚 happening in the future.

Those future projections are often key and they have wide ranges, but mostly it鈥檚 due to the human factor. The reports spell out what happens if the world drastically reduces emissions of heat-trapping gases, what happens if it doesn鈥檛, and what happens in between.

That鈥檚 a key point in these reports: The future isn鈥檛 set. It depends on what鈥檚 done in governments, businesses, and homes.

Because these reports come out every five to eight years, the next set of reports will likely come out as the world is within a tenth of a degree or two of that 1.5 degree goal.

So climate scientist Zeke Hausfather of the Breakthrough Institute said he suspects the next version of this report won鈥檛 be so much about how to prevent 1.5 degrees of warming but 鈥渨hat would be needed to bring global temperatures backdown to 1.5 in the 22nd century.鈥�

Who reviews the climate report?聽

The report does not do new science. It is all based on previously published peer-reviewed science.

Scientists write the report, which then gets reviewed by other scientists, governments, and others. There鈥檚 a giant report with more than 1,000 pages, but the real key is called the Summary for Policy Makers, showing how this is aimed at world leaders. For the past two weeks, scientists and governments review and rewrite the draft line by line.

The summary has to be approved by consensus and some language gets watered down. It is a slow process that in this case has already passed its Friday deadline.

Most of all of the attention is spent on the summary, which can run into the dozens of pages. But there are 26 chapters or supplements, with some of them concentrating on specific regions, others looking at health, food, cities, or risk.

This story was reported by the Associated Press. Seth Borenstein contributed from Kensington, Maryland, and Frank Jordans from Berlin.