The latest batch of reports from the world’s leading scientific body on climate change reinforces how much work we must do to restore the health of our planet.
Since the Industrial Revolution, humanity has emitted more than one trillion tons of carbon dioxide.1 These emissions have primarily been generated by burning fossil fuels, mostly coal, oil, and natural gas. Fossil fuels have powered industrialization around the world and are essential for the daily livelihoods of billions of people. They help us eat, move, and build in previously unimaginable ways.
When we began burning fossil fuels in the 19th century, the consequences of doing so were not widely understood or considered. Over time, our scientific understanding of the greenhouse effect - a process that occurs when certain gases trap solar radiation in the atmosphere and inhibit its release—has grown.
So have our annual emissions. In 1850, humanity emitted less than one billion tons of CO2 into the atmosphere. In 1950, it grew to six billion tons. Two thousand emissions exceeded 25 billion tons, and we now emit almost 40 billion tons of carbon dioxide into the atmosphere every year.
These emissions have driven economic growth and powered our modern way of life. But they have also caused a climate crisis of epic proportions, which existentially threatens our civilization.
To scientifically catalog the dangers posed by human influence on the environment, the Intergovernmental Panel on Climate Change (IPCC) has been periodically releasing thorough reports on climate change for over three decades. It’s an international body composed of leading scientists who collectively update our understanding of climate change.
To date, the IPCC has released six assessment reports detailing the causes and effects of climate change. They include recommendations in their reports but emphasize that it’s up to all of us to address the climate crisis. And as the science in the most recent assessment report—released in three parts over the last year—makes clear, we have a lot of work to do to restore the health of our planet.
The IPCC doesn’t beat around the bush when it comes to explaining who has caused the climate crisis: it’s us. As the report states, “it is unequivocal that human influence has warmed the atmosphere, ocean, and land.” Since the Industrial Revolution, we’ve boosted the amount of carbon dioxide in the atmosphere by about 50%2 (from ~280 parts per million to ~420 parts per million). And thanks to this atmospheric carbon boost, average global temperatures have risen by 1.2 degrees Celsius3 since the start of the industrial area and are poised to surpass the dreaded 1.5 degrees Celsius threshold within a decade or two.
The latest IPCC report details the physical impacts of the climate crisis with greater confidence, breadth, and depth than previous reports. And the findings are terrifying. Climate change is likely making tropical cyclones more frequent and more severe. It’s doing the same thing to other heavy precipitation events as well as heat waves. It’s making cold waves less frequent and less severe. As such, up to 3.6 billion people - almost half of all the human beings alive—already live in areas “highly vulnerable to climate change.”4
Since the previous assessment report was released in 2013, scientific advances have allowed for better projections of climate impacts around the world. For instance, even at 1.5 degrees Celsius, heavy rain and flooding are projected to intensify in affluent and less affluent areas, dispelling the notion that one can escape the climate crisis. If emissions were to continue, additional warming would lead to exponentially worsening impacts.
As the Washington Post summarized in February, “projected loss of forests and thawing of permafrost under some of the worst-case warming scenarios would add the equivalent of 15 years’ worth of greenhouse gas emissions to the atmosphere. But curbing warming to below 2 degrees Celsius would cut emissions from these ecosystems by more than half.”5
Likewise, the number of people who will live in areas exposed to water scarcity is projected to be about a billion higher at 2 degrees of warming relative to 1.5 degrees.
Arguably the most insidious aspect of the climate crisis is the stark disparity between the parts of the world that have principally caused it and the areas that will suffer most from it. For instance, Africa has contributed less than three percent of cumulative global emissions but is projected to experience over half of the near-term excess deaths from climate-related illnesses.6 And over the last decade, the average number of deaths from floods, droughts, and storms in countries considered “highly vulnerable” was 15 times higher than in places with low vulnerability.
The fact that the people most vulnerable to the climate crisis are the least equipped to adapt to it is both sad and highly concerning. That’s not to say wealthier corners of the world won’t suffer from the pollution they have unleashed on our planet. Extreme heat already devastated Europe more than a month ahead of peak summer temperatures, and last year’s Pacific Northwest heatwave was one of the worst in recent memory.
But the science makes it clear that those sorts of extreme weather events will occur more often in poorer areas like South Asia, where a relentless heatwave earlier this year7 killed 90 people, and ongoing flooding has displaced millions of people. These events are a disturbing preview of what’s to come. The amount of money and resources needed to help these areas cope with the climate crisis is significant, but it’s certainly manageable, and the glaring lack of support from wealthier parts of the globe like North America and Western Europe is a deadly choice that will prove devastating for millions of people
Circling back to the physical impacts of climate change, perhaps the most ominous scientific takeaway from the report relates to tipping points. These are abrupt and irreversible changes to major natural systems whose dangers lie largely in their unpredictably.
Arguably the most menacing tipping point is the melting of ice around the world. As the sixth assessment report states, “mountain and polar glaciers are committed to continue melting for decades or centuries (very high confidence). Loss of permafrost carbon following permafrost thaw is irreversible at centennial timescales (high confidence). Continued ice loss over the 21st century is virtually certain for the Greenland Ice Sheet and likely for the Antarctic Ice Sheet.”
This global thawing - of glaciers, permafrost, and sea ice, among other forms of freeze - presents an avalanche of risks for human civilization. It will raise sea levels, imperil drinking water availability, expose us to dangerous viruses that have been dormant for ages, and amplify warming by reducing the albedo effect and thereby increasing surface level absorption of solar radiation.
Other tipping points the report states cannot be ruled out include the collapse of major oceanic currents and the collapse of rainforests. A 2021 study found that the Atlantic Meridional Overturning Circulation is currently at a “point close to a critical transition.”8 A destabilization of this global current could lower temperatures in the Global North while increasing sea levels.
And scientists have already confirmed that the Amazon rainforest emits more carbon than it absorbs.9 This trend exemplifies how climate change is interconnected with other examples of human influence. In the case of the Amazon, rampant deforestation to clear land for logging and agriculture releases large reserves of carbon previously stored in trees into the atmosphere and limits the rainforest’s ability to absorb carbon in the future. Wildfires - whose severity and intensity are exacerbated by the climate crisis - also kill rainforest vegetation and magnify the Amazon’s conversion into a carbon source rather than a carbon sink. Seeing as rainforest ecosystems are a major carbon sink, and the Amazon is the world’s biggest rainforest, this news is unsettling in both the short and long term.
In short, these tipping points should make us all very afraid of the climate crisis and very motivated to act.
Extreme weather events like unprecedented heatwaves and biblical floods underline another inconvenient truth we must wrap our heads around. For a long time, politicians have framed the climate crisis as something to be addressed for our children and grandchildren. That’s true, but it obscures the fact that we need to address it for us because it’s already affecting us on a massive scale.
Here’s another inconvenient truth: every gram of carbon we emit into the atmosphere matters. There’s no “point of no return” or threshold beyond which we are all doomed. Instead, we have the power to control our fate as a civilization. It will never be too late to act in some way. And when we stop polluting our planet with greenhouse gases, our planet will stop warming almost instantaneously.
We could use that to justify the continued delay. Or we could instead consider how quickly we can start undoing the climate crisis by acting decisively and proactively. The just transition to fossil fuels is both inevitable and long overdue. Every day we wait is both a lost opportunity and a death sentence for life on Earth.
In a nutshell, if there’s anything to take away from the latest IPCC report, it’s that we know very well how much catastrophic damage we will inflict based on how much we emit, and we know how to change society to avoid emitting greenhouse gases, but we don’t want to.
UN secretary-general António Guterres, a leading voice for climate action, said some governments and businesses were “lying”11 in claiming to be on track to keep warming below 1.5 degrees Celsius. Guterres warned, “some government and business leaders are saying one thing – but doing another. Simply put, they are lying. And the results will be catastrophic.”
You might say that the world’s most powerful leaders are telling us a version of what Jack Nicholson famously yelled at Tom Cruise in A Few Good Men: we can’t handle the truth. More than 15 years after Al Gore released An Inconvenient Truth, the truth about the climate crisis is still considered inconvenient by the people who count, the people who have the power to fix this mess but lack the will to do so.
The good news is that some of the losses we’ve inflicted on ourselves are reversible. The science is clear that if we quickly cut emissions, temperatures will stop rising shortly thereafter - likely within a decade or two. Furthermore, the increases in extreme weather events that accompany said temperature rise would be greatly limited. In essence, many of the planet’s major systems are dynamic. Just as we got ourselves into the mess, we can extricate ourselves from it somewhat.
But the scale of emissions cuts and absorption scientists assert are needed will require a rapid transition away from fossil fuels. To have a chance to permanently curb global warming below the critical level of 1.5 degrees Celsius, we need to stop releasing greenhouse gases into the atmosphere and remove greenhouse gases from the atmosphere.
More than anything, as one article discussing the IPCC’s latest findings, said, it “will require a reshuffling of society on a scale unseen in human history. It would be akin to cramming all the medical advances made between penicillin and today’s mRNA vaccines into a few beautiful decades.” Individual countries and alliances have acted forcefully in wartime on these sorts of collective scales to make rapid changes, but the level of global engagement needed to transition away from fossil fuels cannot be understated.
As scary as the facts are, the climate crisis presents a compelling opportunity to reshape some of the worst aspects of modern civilization. Our fossil-powered world creates a lot of undue suffering and death. Air pollution alone kills about nine million people every year, and those deaths are mostly independent of the greenhouse-related warming effect of pollutants like carbon dioxide.
This is a choice that we can and must undo on multiple levels: the supply of fossil fuels is finite, and so is the amount of damage we can induce on ourselves without cataclysmic levels of suffering and disruption to our daily levels. Nonetheless, we are quickly running out of time to avert catastrophic warming scenarios that would disrupt wide swathes of the planet, threatening our ways of life and rendering parts of the planet inhabitable for humans.
With every report, the IPCC has sounded a louder alarm about the extent of the damage and our ability to clean up our mess. For three decades and counting, the evidence outlined in its reports has gotten stronger - more comprehensive, more certain, and more concerning.
And yet our collective response has not matched the urgency highlighted in these reports and what they represent: a growing body of proof that we have “unequivocally overheated the planet” and face “ever-worsening impacts” the longer we wait to act decisively in the face of an existential threat.
One of the biggest debates in the climate community is whether individual climate action or systemic climate action is more important. This question touches on both ethical norms and empirical truths, but the debate often misrepresents the truth of the matter, which is that both matter. You matter, and we matter.
To me, the less individual you interpret your sphere of influence to be, the more impact you can have. Yes, it would help the planet if you were to fly less or eat less meat. It would help a lot more if you would leverage your voice to influence others’ behavior, particularly if you can influence people who also have more influence on climate change, either by way of their own emissions or by their ability to affect change.
Talking with your friends and family is perhaps the easiest and most effective way to speak up. You’ll feel more comfortable discussing sensitive issues like this with them, and they’ll likely trust your words more than conventional sources of information like politicians, scientists, or government agencies since you can connect over shared values and experiences. Preeminent climate scientist Katharine Hayhoe gave a widely popular TED Talk about this very topic in 2018.
There are other ways to get engaged, too, depending on what you bring to the table. You can pressure your employer to be more sustainable. You can engage with other members of your community by talking to your neighbors, for instance. And you can always join collective action to affect change at local, regional, national, or even international levels.
Lastly, you can always keep learning. The climate crisis is here to stay. Our understanding of it is always evolving. The IPCC won’t stop releasing assessment reports anytime soon, and each successive report will describe the climate crisis with greater detail and clarity. Of particular concern, the most recent report might be the last one released before widespread irreversible changes begin across the planet.
As such, your understanding of the climate crisis should evolve as well. Its impacts are growing, and no matter where you come from or where you live, it will touch you in some way. The more you know, and the more you share, the more you can mentally and physically prepare yourself and those you love.
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