Why August 9 is a huge day for climate action
For climate scientists and anyone concerned about the planet August 9 is the date theyve been waiting for the last eight years. The IPCC (Intergovernmental Panel on Climate Change) will release a mammoth, detailed report combining the best and latest climate science from around the world, its first since 2014. This planetary health check will set the scene for Novembers pivotal UN climate summit in Glasgow. Lets explain why this is such a big deal. All of us including Governments, councils and businesses are making decisions about how to prepare for climate change. Is buying that coastal dream home a good idea? Will my crop be safe from drought? Does this apartment need air-conditioning? Is that a good place for a stadium? But the main source of evidence for these decisions the reports of the IPCC are updated painfully slowly, even though climate science is being updated all the time. Theres a good reason for the slow pace. The reports require co-operation by hundreds of scientists, drawing on a globes worth of published research. The process works by consensus , and involves a lot of cross-checking. The writers dont get paid, and have to fit their reading, assessing, debating and late-night Zoom meetings around other, full-time jobs. READ MORE: * How water vapour in the air adds to the greenhouse effect * Methane from farms, waste and fossil fuels rising * Sea walls protecting New Zealand cities are losing their battle with the ocean, UN report warns To help fill the void between reports, the IPCC put out some interim reports since the last full version most notably its report on the importance of trying to stay inside 1.5C heating . That prompted governments including New Zealands to commit to a 1.5C target . In 2018, Christchurch hosted an authors meeting for another interim report, on food and land . But the slow-cooked, full report is considered the most authoritative. The next one, due on August 9, will be the first in a set of three and early hints suggest the news could be bleak, even by climate change standards. The first segment in August will cover the source of the problem, or what our greenhouses gases are physically doing to the planet. The second, due in February 2022, will outline the impacts on us, the people, and the species we share Earth with. The third, due March 2022, will canvass what we can do about it. The clue is in the title, Assessment Report 6 or AR6. This is the sixth time this process has been repeated since 1988, hence the number of the working group. Since then, the amount of published research has exploded, and so have greenhouse gas emissions, says New Zealander and vice chair of an IPCC working group, Andy Reisinger. Each time, authors from around the world look at all the studies measuring global temperatures , the greenhouse effect and the impact of a hotter climate on cities, food production, diseases, sea level rise, fisheries and other things. Combining a huge range of peer-reviewed research from different fields helps eliminate bias and errors that might occur in any one study. (A similar, albeit smaller process of synthesising individual medical trials is often done to determine whether a medicine is effective.) There are always differences of opinion about emerging areas of research, like, which model best reflects the pace of melting ice sheets? Resolving those has been more difficult than ever, because the scientists couldnt meet personally, because of Covid. An already-fractious process was made more painful on email, because disagreeing writers couldnt meet for a beer afterwards, and didnt have to face each other over a table, says Victoria Universitys Dave Frame. As for whether anyones listening, well, government pledges to cut climate pollution are still well below whats required to keep heating inside 1.5C or even 2C . New Zealand is no exception . But signatories to the global greenhouse-cutting Paris Agreement have until November to put forward better efforts. Thats when a pivotal UN summit will be held in Glasgow, to negotiate some of the last remaining details on how to keep us all under 1.5C heating or, at worst, 2C. The conference, known as COP26, was pushed back a year because of Covid. The UK Government has been pushing hard for countries to go all out. Its hoped the release of this report could provide an added incentive, by highlighting the cost of failure. The writing group is made up of climate scientists from academic institutes across the world, and the full list is available online . Theres a hierarchy: Korean energy policy specialist Hoesung Lee has been the IPCCs big boss, aka chair, since 2015. Below him are three vice chairs, from the US, Brazil and Mali . The two highest-ranking Australasians are Reisinger and Aussie Mark Howden, of Australian National University , both climate and agriculture specialists. They are vice chairs of two different working groups , putting them both on the IPCC steering body. As well as doing his core research , Reisinger attempts to help people understand IPCC reports by boiling them down into haiku , which he posts on social media. Each chapter of the full report has two or three coordinating lead authors (aka group leaders), plus between 10 and 15 lead authors. Another two to three scientists act as review editors. Its perhaps not surprising discussions can get a bit cranky: the second draft of the report were about to see received 51,000 review comments. Each one had to be individually answered, in writing. New Zealand typically contributes a handful of authors whore considered experts in their areas. For example, Victoria Universitys James Renwick (once of our Climate Change Commissioners) is a coordinating lead author of AR6. So is University of Canterburys Bronwyn Hayward, whos a coordinating lead author of a chapter about cities, settlements and infrastructure. Other Kiwi authors include the climate commissions Harry Clark (a lead author in the agriculture and forestry section), Victoria Universitys Frame (a lead author of the part covering Earths energy budgets and climate feedbacks) and Lincoln University's Anita Wreford (a lead author of the Australasia chapter.) After the scientists have compiled their draft, the report is opened up to other experts and governments to provide feedback. Fair question. The answer often given by the scientists is that its governments who need to accept and act on the findings, if were to get a handle on climate change. Giving them a chance to review the draft before the rest of us see it increases the chances of political buy-in, or so the argument goes. And, technically, the IPCC is made up of governments they just get scientists to do the work. The finished document is a huge beast, packed full of citations, so the writers prepare a high-level summary, called the Summary for Policymakers. This is the version that is actually read by most people, including most politicians, who engage with the reports. Over the next two weeks, government representatives will be meeting with key scientists involved in the first part of AR6 to go over and agree every line of this summary. However, Reisinger says the scientists dont let political reps make changes that arent true to the science. They cant change black to white. Authors are sworn to secrecy during the process. Renwick, however, suggests the findings will be stark. One area to watch for is sea level rise, where researchers have been busily updating and comparing their ice sheet models. An interim report on ice and the oceans showed scientists had grown more confident in their models since 2014, enough to increase the upper bounds of melting from Antarctica. A third of Antarcticas ice sheet sits below sea-level, making it vulnerable to widespread collapse as the world around it warms. The interim report highlighted the need for more work to understand this risk, given Antarctica alone could raise the sea by several metres, not including melted ice from Greenland and the world's glaciers. Victoria Universitys Nick Golledge, who's helping write AR6s oceans section, says the differences between ice sheet models are now understood well enough that AR6 will be able to explain more clearly what scientists dont know about future melting, as what bits of the science are solid. It doesnt mean the unknowns have gone away, but we can differentiate between them better. Stay on top of the latest climate news. The Forever Project's Olivia Wannan will keep you in the know each week. Sign up here .