Climate Change Checkup: 2023 Edition
Today we've got something a little bit different for you. Think of it as my "state of the climate" address. We're going to talk about what's real about climate change, what's not, where we stand, and what we're probably getting ourselves into. We'll get started with some hyperbole.
The major impetus for this episode today were come comments made by Al Gore at the World Economic Forum in January 2023. He was clearly upset, and I believe it can only reasonably be characterized as a rant. When I say "rant" I mean only to characterize his tone, not his accuracy. He was clearly on a high-emotion tirade. Here is a brief snippet from his much longer remarks:
What happened next is that the portion of the mass media that generally trivializes climate change focused on Gore's phrase "boiling the oceans." No intelligent person, Gore included, actually thinks the oceans are literally boiling. He was speaking metaphorically, and any reasonable person knows that; so it's kind of a waste of life to pretend you think he was making a factual claim. But everything else he said was absolutely right. We are adding that much CO2 to the atmosphere every day, and that's easy to directly measure simply by sampling the atmosphere. We can prove that added CO2 comes from burning fossil fuels by isotopic analysis of the carbon. It is trapping an additional 600,000 Hiroshima bombs of heat in the atmosphere every day, and we can directly measure that too, by measuring the temperatures at all the levels in the atmosphere by balloon and by satellite. The heat the Earth used to radiate out into space gets trapped in the atmosphere because the greenhouse gases block out the part of the infrared spectrum where that heat used to find an open window, and we find the highest parts of the atmosphere are getting colder because that heat is no longer making it out there. All of these things can be directly measured and all that data is in the public record.
Nobody complained about Gore's mention of atmospheric rivers, because we've all been seeing these unprecedented floods and storms the past few years. Nobody complained about his rain bombs, also called microbursts, because we've all seen the record-smashing single-day rainfalls. Warmer temperatures result in more evaporation — the "sucking the moisture out of the land" that Gore mentioned — resulting in more water in the clouds, way too much for them to hold onto, causing it to dump in what meteorologists call rain bombs. He mentioned droughts and loss of ice and rising sea levels, and nobody complained about those because we all see it in the news every single day. Nope — just the boiling oceans.
The real problem is that this came from Al Gore, a polarizing political figure. This means that 50% of the population is likely to find only fault in anything he says, and the other 50% is likely to find only truth in everything he says. As a whole, we tend to practice tribalism much more than we practice rising above it in favor of finding an objective perspective on science issues. Focusing on his one metaphorical phrase "boiling the oceans" and ignoring all the rest, is pure tribalism, practiced only by those who deliberately avoid hearing science facts.
There was also a second impetus for this show. A few weeks ago I did a show on the Top Anti-Experts in each of 10 science fields, and for the anti-expert on climate change, I chose the Danish libertarian political scientist Bjørn Lomborg — also a polarizing political figure, and from the opposite end of the political spectrum from Gore. Almost all the feedback I got on that episode was about his inclusion. Liberals and scientists universally praised his inclusion; libertarians universally condemned it. This was a frustrating moment for me.
How often can I beat this drum on Skeptoid? Stop getting your science from politicians. You wouldn't go to the gas station for the best sushi; why would you go to politicians for the best science?
I don't care if it's Al Gore or Bjørn Lomborg or anyone else that you love or hate; you shouldn't be getting your science from either one of them. If there's any one thing I've repeated the most in 17 years of the Skeptoid podcast, it's to stop getting your science from politicians. And so many listeners still seem to have missed that.
So where should you go for your climate science? There are many great places. Some of them are sources like NASA Earth Science, the European Space Agency's ESA Climate Office, the IPCC (Intergovernmental Panel on Climate Change) or the WMO (World Meteorological Organization) — and before you say "Oh, I won't listen to them because they're part of the United Nations" — then what I'm hearing you say is that your politics should determine where you're going to get your science. If that's you, then rewind about 60 seconds, and repeat as many times as necessary.
What you'll get from any and all of these sources are the same findings. All of these websites have executive summaries, explainers, introductions, and so on — if you find one too confusing, move on to another. The bottom lines are basically all the same.
The big number to follow is that 1.5°C. As global average temperatures rise relative to what they were in the preindustrial period — before humans started burning fossil fuels — a limit of 1.5°C will avoid the costliest damage to world systems. And when we talk about systems, we're talking about many: economic, agricultural, health, oceans, atmospheric, and all the countless variations of systems in different parts of the world. These temperatures are calculated as the 30-year global average of combined air temperature over land and water temperature at the ocean surface, so it's a strong, comprehensive number.
Currently we are between 1.1°C and 1.2°C, depending on the source. Now, that's global; there are regional variations all over the place. Right now our upward trajectory is about a quarter of a degree per decade, and it's been in that neighborhood for about 40 years. But the rise has been steepening for most of that time. To avoid 1.5°C, we have to achieve 50% net reduction in greenhouse gases by 2035, and we have to achieve net zero by 2050. If we can meet those reductions, then most probable scenarios will just barely keep it under 1.5°C.
"Most probable" is an important thing to note. All of this stuff is done in probabilities, never in specific predictions. If you hear someone say something like "climate scientists missed their predictions," well, that person doesn't know what they're talking about. Climate scientists compute probabilities, and don't make specific predictions.
However, if you read these executive summaries, in many cases they are — forgive the expression — "dumbed down" for non-scientists like lawmakers and policy makers, and sometimes express these probabilities in terms of ranges of specific predictions that people can more easily understand. For example, on the NASA climate website, it says "Sea level will rise 1-8 feet by 2100." What's behind that? Well you can drill down, and when you do, you find that it takes into an account an achievable aggressive reduction, and a likely continuation with little reduction, and gives the most probable outcome of each. So 1 foot of sea level rise has a certain probability, and 8 feet has a probability; there's likely a higher probability of something in the middle, and there's a probability for every number outside that range too. There's a probability of 20 feet of sea level rise, and of sea level dropping. Such scenarios are likely very very low probabilities, but they're calculable.
For the current status, sea level is up 200mm (about 8 inches) since 1900. The upward trend is currently accelerating, and this acceleration will continue. Sea level rise trails atmospheric CO2, and atmospheric CO2 has been accelerating throughout the past century. Some amount of sea level rise is inevitable, and we're past the point of hoping we won't have to relocate some communities all around the world. Some will have to be relocated, some might be protectable with dikes, it's going to be a matter of what's most probable balanced against cost. Sea level rise is driven by two factors: expansion of warmer water, and additional water from glacial melt, both of which are continuing and currently accelerating.
We're now at 420 ppm of atmospheric CO2. Preindustrial it was around 280. The graph shows a sharp upward trend with no sign of slowing yet. Reduction of emissions is the single most important thing we can do. See Skeptoid #797 for a deep dive into why reducing methane is the best way to make the most progress soonest.
Loss of ice sheets is a huge factor. We're losing about 275 billion tons a year from Greenland, and about 150 billion per year from Antarctica. The way the Greenland ice sheet is structured means there's a chance it could all go, and if it does, we'll be at a sea level worst case scenario. That's still an "if" but every year the temperatures keep rising brings it closer to a "when".
In the 10 years between 2009 and 2018, 14% of the world's coral reefs died, caused by acidification (adding CO2 to the oceans) and warming water temperatures. Heat stress on the Great Barrier Reef caused 85% bleaching with 29% mortality in 2016. 51% of all reefs worldwide are under heat stress.
For more proof that you can see with your own two eyes, look no further than glaciers. We just had the 35th year in a row that glaciers worldwide shrank. The loss rate between 2010 and 2020 is twice what it was between 1990 and 2000, and quadruple what it was between 1970 and 1980.
Claims that the costs of fighting warming would cripple world and national economies are false. It doesn't work that way. Economists have been shouting this from rooftops for decades. The way a carbon tax would work, in very brief terms, is that activities that increase emissions would be taxed, and activities that decrease emissions are stimulated by receiving those taxes as incentives and refunds. There are endless ways these economic levers could be put into action, but one thing they all have in common is disincentivizing fossil fuels and incentivizing renewables. This is the way the whole world is going anyway: Fossil fuels are dying industries, across the board, shrinking every year as costs increase and yields decrease; renewables are growth industries. Anyone with their eye on tomorrow's finances is already moving away from fossil fuels. Carbon taxes would simply accelerate things in the direction they're naturally moving anyway — to the benefit of everyone, and to the utter destruction of absolutely nobody's economy. For a deeper dive, see Climate Tax Basics from the Center for Climate and Energy Solutions, a nonpartisan environmental think tank.
Conversely, the costs we're bearing now and will continue to suffer from the effects of warming will absolutely be enormous. Regions accustomed to being dry are having to adapt to deal with flooding, and regions accustomed to lots of rain are having to adapt for drought. Crops, livestock, and fisheries have already been affected and these impacts are projected to increase across the board. Seaside communities worldwide will have to move or build massive seawalls. Eventually, national water grids are going to be a must, which will require unprecedented eminent domain actions by governments, to nobody's delight. People talk about engineering our way out of climate impacts, well, that's no longer optional. Engineering projects like what we're facing will be among the biggest and most expensive in history. They're not needed tomorrow, and possibly not even in the lifetimes of most of today's adults. But by 2100, with a likely 4 to 5 feet of sea level rise, they'll be well underway at least.
The good news is that staying below 1.5°C is still achievable. The impacts just discussed are real and unavoidable, but having it get any worse than that is avoidable. It just requires that people prioritize their financial future ahead of party politics — something that is, sadly, too big of an ask for many people.
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