Apocalypse Now: What to takeaway from the brand new, explosive UN climate report?

It will infuriate you at first, but then it will tell you what to do. Don't lose hope yet!

The Intergovernmental Panel on Climate Change(IPCC), a UN body responsible for assessing the science related to climate change and presenting the findings to the world, just released the first of the three parts that will form Assessment Report 6, due to be released in 2022. The first part deals with consolidating all the latest available science on climate change, just the science. The next two parts will deal with the climate change impacts on our world and adaptation + mitigation options.

In this very long post, I try to help you interpret this 4000-page landmark report with plenty of science and actionable items to save ourselves from a long drawn out apocalypse that never ends. I’ve picked 10 key updates that are pertinent to understanding the current and future state of our climate. Read with patience and feel free to comment if you need any further clarifications or if you want to flag any correction. (Link to the report at the end of this post)

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Sidenote: The latest report is titled IPCC Working Group I Sixth Assessment Report (IPCC AR6 WGI). Such boring names for a world disrupting issue, ugh, just writing about it is putting me to sleep. But the contents are unimaginably worse, so I can’t possibly sleep but petition to make names more interesting? Apocalypse For You 2021 Report? Anyhooo …


Before getting to the latest report, let me give you a quick primer on the IPCC reports and process. Let’s also take a moment to appreciate the amount of effort that goes into making these crucial reports that guide the entire world from averting a catastrophe. (Or you can skip this, scroll down for the key takeaways)

The IPCC process:

The IPCC has so far released 5 major Assessment Reports, along with some special reports dealing with specific issues such as SR15 that dealt with mitigation pathways to limit warming to 1.5°C or SROCC that dealt with changes in the ocean and cryosphere. Otherwise, IPCC mainly is responsible for synthesis reports that are called Assessment Reports released once every five years or so to help policy makers, governments, corporates and even citizens understand the latest available climate science, impacts and possible solution pathways.

Climate scientists volunteer to work on these reports, collaborating with hundreds of peers across the world to come up with a technical consensus on the current state of climate and future predictions. An executive summary of this technical report is then shown to government representatives worldwide, from all countries party to UNFCCC treaty, to get their approval on the language. The science content approved by scientists cannot be altered but how you say it can be altered by government representatives or they can request further clarification/additional information. This is done so that by the time governments meet at COP, no one can dispute the science because the report was already approved by the governments. This summary becomes the Summary for Policy Makers (or SPM in short) that informs the negotiations in COP, leaders can now get down to business instead of squabbling if the statements in the report are accurate/exaggerated/understated or not.

What happens behind the closed doors though?

Apparently media is not allowed to report from inside the negotiating rooms where scientists and government representatives negotiate the language of the SPM report. But Earth Negotiations Bulletin, an independent reporting service is allowed to attend the negotiations and present a report after the plenary is closed for the sake of transparency and accountability in international policy-making.

You can see this year’s full negotiation report here - Summary of Working Group I sessions: 26 July - 6 August 2021

For instance, as per the report above, several countries demanded this Headline Statement “human influence has warmed the climate system, and widespread and rapid changes in climate have occurred.” be made more clear and strong while Saudi Arabia, India and China proposed watering down the statement “observed warming of the climate system is unequivocally caused by human influence” to “human influence has warmed the climate system”.

Ultimately, it became “It is unequivocal that human influence has warmed the atmosphere, ocean and land. Widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere have occurred.”

This process is repeated for every single line that goes into the Summary for Policy Makers report. But once approved, there’s no disputing the science or statements.

Also this entire thread is a worthwhile read for a peek into international negotiations.

For the latest AR6 Working Group 1 report, over 230 scientists reviewed over 14000 scientific papers to produce a 4000 page report!

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So what are the key takeaways according to me?

Here we go -

1. There’s nothing new yet there’s a lot that’s new!

I’ve been following and reporting on climate for just two years now. This is the first IPCC report release that I’ve actively followed and read. I was gallivanting in some stunning corner of the world when Paris Agreement was signed in 2015. I was barely bothered when the limiting warming to 1.5 degree report was released in 2018. And yet, in just the last two years I already feel like a broken record stuck on “the planet is burning”. But climate scientists and activists have been stuck on that broken record for nearly 30 years now!

In many ways, it feels like nothing much has changed since the first IPCC report was released in 1990. It took them 30 years to go from “humankind is capable of raising the global-average annual-mean surface-air temperature” in 1990 report to “It is unequivocal that human influence has warmed the atmosphere, ocean and land” in 2021. They are sadly still repeating the same statement with more and more certainty, begging for the world leaders to act in accordance to the threat level but all of this still seems to be falling on deaf ears, leading to unstoppable and irreversible changes in our climate system. And so while on the action front, seems like a lot is left to be desired, things have been developing fast on the science front, as you can read below.

2. New numbers are here, on the present state of climate and the future

First, the earth’s surface has now warmed by 1.07°C compared to 1850-1900 average.

Second, The Equilibrium Climate Sensitivity(ECS), which got an update recently after many decades, was incorporated into the latest report. The best estimate for ECS is now 3°C. Google more on ECS if you want but what you need to mainly know is just that ECS is crucial in estimating how the climate responds to the heating. This update has given us improved certainty in terms of temperature rise predictions under different emission scenarios.

Third, the latest report uses five emission scenarios known as SSPs, Shared Socioeconomic Pathways, to predict how the earth’s surface will warm corresponding to a particular level of greenhouse gas emissions. You may want to memorise these names and what they mean because we’ll be stuck with these emission scenarios for the next couple of years when discussing emission reductions and pathways. Between SSP1-1.9 and SSP5-8.5, the temperature rise ranges from 1.4°C to a maximum of 4.4°C by 2100.

SSPs Explainer on National Geographic: 5 possible climate futures—from the optimistic to the strange.The five scenarios that form the backbone of the latest IPCC report tell radically different stories about humanity’s future.

3. Attribution science has come of age, so to speak, with this report.

For the longest time, even though it was generally accepted that global warming causes more intense heatwaves, extreme flooding and rainfall, more intense fire seasons etc, meteorologists and climatologists were afraid to directly link a particular event to climate change. All of that changed in the recent years though, when climate scientists figured out a quick and reliable way to find the footprint of climate change in extreme weather events. And I personally think this is a game-changer because now we not only know and feel the climate changing, we can also be certain that it is making things worse for us.

No scientist would have been secure in making such a rapid and decisive statement until a few years ago. Normally, it would take months or years to research, peer review and publish findings. Instead, WWA[World Weather Attribution] runs hundreds of computer simulations to compare the probability of an event occurring in the world as it exists and one in which there are no greenhouse gases added by humans. That has brought a new speed and certainty to the slow-moving and tentative world of climate science. 

— Read more at The climatologist who put climate science ‘on the offensive’. Friederike Otto has tailored her research to beat back doubt about the link between extreme events and climate change.

4. The Past is speaking to us with more and more certainty, and is the bearer of much bad news.

Paleoclimatology is the study of previous climates that have existed during Earth's 4.5 billion years of history using something called proxies that provide indirect data to reconstruct what happened in the past, so we can better predict our future climate under similar climatic conditions. The latest IPCC report incorporates rich paleoclimate data to do two things — 1. inform us how unprecedented the current trends are in the sense that the climate hasn’t changed this rapidly in millions of years and 2. how unrecognisable the climate was when greenhouse gas levels were this high in the past.

The scale of recent changes across the climate system as a whole and the present state of many aspects of the climate system are unprecedented over many centuries to many thousands of years, as per the report. Atmospheric CO2 concentration hasn’t been this high in the past 2 million (20,00,000) years. The temperature hasn’t been this warm in the last 1,25,000 years. Arctic sea ice cover hasn’t been this low in the last 1,000 years at least. Global glacier retreat at current rates hasn’t happened in the last 2,000 years at least.

What all of this means is that we do not have time to adapt to these superfast changes in the climate and environment and evolve accordingly, you know, the normal process of evolve or go extinct formula that living creatures have been following for millions of years now.

Read more at Paleoclimate Data Raise Alarm on Historic Nature of Climate Emergency. The new Intergovernmental Panel on Climate Change report uses data from our planet’s distant past to better understand current warming

And I would highly, highly recommend you bookmark this longread to understand why the paleoclimate data is bad news!

Read on The Atlantic, The Terrifying Warning Lurking in the Earth’s Ancient Rock Record. Could Climate Change Be More Extreme Than We Think?

5. 1.5°C warming is locked in no matter what we do. Whether it is a temporary spike or a more permanent one is up to us.

Each of the five SSPs correspond to a specific carbon budget, that is the amount of greenhouse gases that will pumped into the atmosphere in the coming years. The sad realisation from the latest report is that irrespective of whether we follow the very low emission scenario or the very high emission scenario, breaching 1.5°C is inevitable, as you can see in the table below.

(Best estimate and very likely range are self explanatory I suppose, but if not, here’s what it means. If we take the first row, under SSP1-1.9 scenario, the average temperature increase during the 20-year period of 2021 to 2040 could be anything within the range of 1.2 to 1.7°C, best estimate being the temperature increase could be 1.5°C)

The one ray of hope is that under the two low emission scenarios, SSP1-1.9 and SSP1-2.6, the temperature stabilises at around 1.4°C and 1.8°C by 2100. These are the only two scenarios that meet the Paris Agreement target. The catch, however, is that for both of these emission pathways to work, the global greenhouse gas emissions need to peak by 2025, i.e. in the next four years, and then gradually go down to netzero by 2055 and 2075 respectively. Not just that, there is also heavy reliance on magical negative emissions, i.e. sucking CO2 from the air in order to reach the 1.4°C and 1.8°C targets by 2100. Yeah, the odds are stacked against us but the three other scenarios straight up lead to us digging our own hot and wet grave.

This figure shows the amount of allowed annual CO2 emissions from 2015 to 2100 corresponding to each emission pathway. See how the two low emission scenarios peak around 2025 and go down from there? And see the grey part at the bottom? That’s the negative emission period where we are actively sucking CO2 from the atmosphere after reaching net zero. Source: IPCC AR6 WG1 Report

6. Sea levels will continue to rise and glaciers will continue to melt

Because climate feedbacks are very, very, very slow, the amount of the CO2 that’s pumped into the atmosphere already will continue to sustain these processes for centuries, even after emissions have stabilised. This process is called climate stabilisation where the earth systems respond to the heat in their own way, on their own time. And the overall warming of even 1.5°C is enough to sustain these processes in the long run. So, oceans will continue to take up heat and respond slowly. As will the glaciers, they will continue to melt over the next many decades and even centuries.

The sea level will continue to rise through this century and continue to rise by several meters over the next many centuries as well, consistent with what paleoclimate data tell us. By 2100, we can expect a sea level rise of anywhere between 0.5m (in very low emission scenario) to 1m (in very high emission scenario) relative to 1900 levels. Over the next 2000 years, sea level is projected to increase anywhere between 2meters to 22meters depending on emissions!

Unfortunately, both these changes are irreversible but temperature and other extreme weather events will respond to emission reductions. So all is not lost.

7. Impacts of climate change are being felt everywhere across the world already

In the latest report, regional climatic projections were included as well with this very interesting design. Here’s how you can interpret this. All the world regions, land and ocean, were divided into 55 zones, each hexagon representing a particular region. India and our neighbouring countries, for instance, are represented as SAS (South Asia). You can see the full reference regions list here.

As you can see, hot extremes are increasing everywhere and the dots represent how much of it was due to human contribution to atmospheric greenhouse gases. Similar illustrations are presented for extreme precipitation and drought as well.

8. Climate change is set to alter all these things in our climate system

It’s not just hot extremes and rainfall events but several other impacts of climate change will be felt across the world with a projected increase or decrease, as shown below. As you can see, surface temperature, sea level, coastal erosion & flooding, heatwaves etc will be on the rise across the world while snow cover and cold spells will decrease globally.

Here’s how you can interpret the chart. Let’s take fire weather parameter (the last one in the Wet & Dry category). The light colored bar represents the 50-odd reference regions where fire weather is relevant. Out of these 50 regions, at least 35 reference regions are projected to see an increase in fire weather, with 14 regions shaded in dark purple certain(high confidence) to see the increase in fire weather and the rest of the regions shaded in light pink also set to see an increase in fire weather, but have a little bit of uncertainty(medium confidence).

9. Carbon budget is dwindling fast and Natural carbon sinks are overwhelmed already

Carbon budget is the amount of CO2 that can be released into the atmosphere till a certain level of warming is reached.

If we want the temperature rise to be limited to 1.5°C, then we have a carbon budget left ranging from 900 to 300 gigatonnes of CO2 (GtCO2). However, the likelihood game is like Russian Roulette, if 900 GtCO2 is released, then we have only 17% chance of staying below 1.5°C. There’s a chance still, but the likelihood is very low. However, if we go with 83% likelihood, then we have a total of 300GtCO2 carbon budget left. As of now, our current annual CO2 emissions hover around 40 GtCO2, so we run out of the 1.5 degree carbon budget in less than 10 years!

Do you know why we haven’t seen terrible warming so far despite the CO2 concentration being terribly, unprecedentedly high? Because the ocean has taken up 91% of the *extra* heat so far, that is also why ocean will continue to process this heat and change accordingly for many millenia. The remaining 9% heat is absorbed by the land(5%), ice(3%) and atmosphere(1%).

Land and ocean both together absorb the natural and anthropogenic CO2 emissions, as part of the earth’s existing carbon cycle. But the more extra carbon dioxide we put in the atmosphere, the more these two natural sinks lose their capacity to absorb the extra CO2, thereby failing to buffer us from the catastrophic impacts of unchecked heating. Since carbon dioxide can stay in the atmosphere for thousands of years and continue to warm the earth’s surface, it is in our best interests to reduce the amount of CO2 that stays in the atmosphere, which is quite large in the latter three scenarios as you can see in the chart above.

10. We will quite probably miss many first targets but we cannot give up!

Seeing how the IPCC and Climate Scientists have been crying hoarse about climate change since 1990s and so little has been done to divert us from the suicide train we’re all on, it can be very easy to lose hope. But I want to say couple of things here on why we cannot afford to lose hope and stop the fight.

  1. Remember last year’s very popular post titled “2020 could actually be one of the best years this century!”? Well, with the unprecedented wildfires, heatwaves and floods that swept across the world, 2021 has already proven to be worse than 2020, hasn’t it? And that’s also exactly why we cannot give up. Even if we miss 1.5°C warming limit, that will still be a better world than 1.6°C warming, which will be better than 1.7°C warming and so on and so forth. You see, the endgame of climate crisis is not a cliff edge that we will jump off at once but instead a slow fire on which we will be roasted for eternity. So any reduction in temperature will make our lives that much easier. It’s okay if we miss targets, the future can be much worse and we can make it a little less worse. And that’s also what the latest IPCC report says.

    “With every additional increment of global warming, changes in extremes continue to become larger. For example, every additional 0.5°C of global warming causes clearly discernible increases in the intensity and frequency of hot extremes, including heatwaves (very likely), and heavy precipitation (high confidence), as well as agricultural and ecological droughts in some regions (high confidence).”

  2. Here’s one small bit of good news. Under low emission scenarios, visible decrease in temperature rise and reduction in extreme climatic events can happen as early as within two decades of strong emission cuts. (The corresponding IPCC text is a bit technical but you can take my word for the plain speak interpretation.) This means we can actually see the temperature responding to our actions and also extreme weather events becoming a little less extreme within our lifetimes!

    Scenarios with low or very low greenhouse gas (GHG) emissions (SSP1-1.9 and SSP1- 2.6) lead within years to discernible effects on greenhouse gas and aerosol concentrations, and air quality, relative to high and very high GHG emissions scenarios (SSP3-7.0 or SSP5-8.5). Under these contrasting scenarios, discernible differences in trends of global surface temperature would begin to emerge from natural variability within around 20 years, and over longer time periods for many other climatic impact-drivers (high confidence).


Call to action: So what do we do with this information?

Here’s what we can do! Climate scientists have done their part and have apprised us of the latest on the state of climate science. All governments have approved it as well, so no one can deny what’s happening to our planet.

COP26 is happening in less than 3 months on Glasgow and the road to this COP is crucial. Let’s make sure neither media nor politicians forget that we have to act on climate now. Learn the science, remember the talking points and do whatever you can to achieve these outcomes. So what do we want?

  1. Strong greenhouse has emission cuts that limit warming to 1.5 °C. (If you are unsure where or who should achieve these emission cuts, read this explainer)

  2. Stronger pledges from countries worldwide to reduce emissions in line with Paris Agreement

  3. Assistance, both monetary and technological, to help countries adapt to climate change.

  4. No greenwashing and actual plans to get to net zero by 2050


Finally, here’s the report link to the up-to-date physical understanding of the climate system and climate change, bringing together the latest advances in climate science, and combining multiple lines of evidence from paleoclimate, observations, process understanding, and global and regional climate simulations.

AR6 Climate Change 2021: The Physical Science Basis

Read the summary of the report here.


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