I’m going to say something that will probably seem completely outrageous. But I want you to think about it, because it’s true.
You, where-ever you are now, are living through the first stages of a disaster in which there is nowhere to run, nowhere to hide, and no safe place on Earth for you to go to avoid it. The disaster you are now living through is a greenhouse emergency and with each ounce of CO2, methane and other greenhouse gasses you, I, or the rest of us, pump into the air, that emergency grows in the vast potential of damage and harm that it will inflict over the coming years, decades and centuries. The emergency is now unavoidable and the only thing we can hope to do through rational action is to reduce the degree of harm both short and long term, to rapidly stop making the problem worse, and to put human ingenuity toward solving the problem rather than continuing to intensify it.
But damage, severe, deadly and terrifying is unleashed, in effect and already happening, with more on the way.
* * * * *
(Michael Mann’s famous Hockey Stick graph showing Northern Hemisphere temperatures over the past 1,000 years. The influences of human warming become readily apparent from the late 19th to early 21rst centuries. But human greenhouse gas forcing has much greater degrees of warming in store.)
This week, Michael Mann wrote an excellent piece describing the immediacy of our current emergency in the Scientific American. In typical, just the facts, fashion, he laid out a series of truths relevant to the current greenhouse catastrophe. These facts were told in a plain manner and, yet, in a way that laid out the problem but didn’t even begin to open the book on what that problem meant in broader context.
Michael Mann is an amazing scientist who has his hand on the pulse of human-caused climate change. He is a kind of modern Galileo of climate science in that he has born the brunt of some of the most severe and asinine attacks for simply telling the truth and for revealing the nature of our world as it stands. But though Mann’s facts are both brutal and hard-hitting for those of us who constantly read the climate science, who wade through the literature and analyze each new report. By simply stating the facts and not telling us what they mean he is hitting us with a somewhat nerfed version of his ground-breaking Hockey Stick. A pounding that may seem brutal when compared to the comfortable nonsense put out by climate change deniers and fossil fuel apologists but one that is still not yet a full revelation.
I will caveat what is a passionate interjection by simply saying that Michael Mann is one of my most beloved heroes. And so I will do my best to help him out by attempting to lend more potency to his already powerful message.
2 C by 2036 — Digging through the Ugly Guts of it
All that said, Michael Mann laid out some brutal, brutal facts in his Scientific American piece. Ones, that if you only take a few moments to think about are simply terrifying. For the simple truth is that the world has only a very, very slim hope of preventing a rapid warming to at least 2 C above 1880s levels in the near future and almost zero hope altogether of stopping such warming in the longer term.
The first set of figures Mann provides involves the current greenhouse gas forcing. Current CO2 levels are now at the very dangerous 400 parts per million threshold. Long term, and all by itself, this forcing is enough to raise global temperatures by between 2 and 3 degrees Celsius. But hold that thought you were just about to have, because we haven’t yet included all the other greenhouse gasses in that forcing.
Mann, in the supplemental material to his Scientific American paper, notes that the total forcing of all other greenhouse gasses currently in the atmosphere is about 20% of the total CO2 forcing. This gives us a total CO2 equivalent forcing of 480 ppm CO2e, which uncannily mirrors my own analysis here (the science may have under-counted a bit on the methane forcing, but this value is likely quite close to current reality for both the short and long term).
480 ppm CO2e is one hell of a forcing. It is nearly a 75% greater forcing than 1880s values and, all by itself, is enough to raise temperatures long-term by between 3.5 and 4.5 degrees Celsius.
And it is at this point that it becomes worthwhile talking a bit about different climate sensitivity measures. The measure I am using to determine this number is what is called the Earth Systems Sensitivity measure (ESS). It is the measure that describes long term warming once all the so called slow feedbacks like ice sheet response (think the giant glaciers of Greenland and West Antarctica) and environmental carbon release (think methane release from thawing tundra and sea bed clathrates) come into the equation. Mann, uses a shorter term estimate called Equilibrium Climate Sensitivity (ECS). It’s a measure that tracks the fast warming response time once the fast feedbacks such as water vapor response and sea ice response are taken into account. ECS warming, therefore, is about half of ESS warming. But the catch is that ECS hits you much sooner.
At 480 ppm CO2e, we can expect between 1.75 and 2.25 degrees C of warming from ECS. In essence, we’ve locked about 2 C worth of short term warming in now. And this is kind of a big deal. I’d call it a BFD, but that would be swearing. And if there is ever an occasion for swearing then it would be now. So deal with it.
Mann, in his article, takes note of the immediacy of the problem by simply stating that we hit 2 C of shorter term ECS warming once we hit 405 ppm CO2 (485 CO2e), in about two to three years. And it’s important for us to know that this is the kind of heat forcing that is now hanging over our heads. That there’s enough greenhouse gas loading in the atmosphere to push warming 2 C higher almost immediately and 4 C higher long term. And that, all by itself, is a disaster unlike anything humans have ever encountered.
(Global annual fossil fuel emission is currently tracking faster than the worst-case IPCC scenario. Aerosols mask some of the heating effect of this enormous emission, what James Hansen calls ‘a Faustian Bargain.’ Image source: Hansen Paper.)
But there is a wrinkle to this equation. One that Dr. James Hansen likes to call the Faustian Bargain. And that wrinkle involves human produced aerosols. For by burning coal, humans pump fine particles into the atmosphere that reflect sunlight thereby masking the total effect of the greenhouse gasses we have already put into the atmosphere. The nasty little trick here is that if you stop burning coal, the aerosols fall out in only a few years and you then end up with the full heat forcing. Even worse, continuing to burn coal produces prodigious volumes of CO2 while mining coal pumps volatile methane into the atmosphere. It’s like taking a kind of poison that will eventually kill you but makes you feel better as you’re taking it. Kind of like the greenhouse gas version of heroin.
So the ghg heroin/coal has injected particles into the air that mask the total warming. And as a result we end up with a delayed effect with an extraordinarily severe hit at the end when we finally stop burning coal. Never stop burning coal and you end up reaching the same place eventually anyway. So it’s a rigged game that you either lose now or you lose in a far worse way later.
Mann wraps coal and other human aerosol emissions into his equation and, under business as usual, finds that we hit 2 C of ECS warming by 2036 as global CO2 levels approach 450 ppmv and global CO2e values approach 540 ppmv. At that point, were the aerosols to fall out we end up with an actual short term warming (ECS) response of 2.5 to 3 C and a long term response (ESS) of about 5 to 6 C. (Don’t believe me? Plug in the numbers for yourself in Mann’s climate model here.)
So ripping the bandaid off and looking at the nasty thing underneath, we find that even my earlier estimates were probably a bit too conservative and Mann, though we didn’t quite realize it at first, is hitting us very hard with his hockey stick.
What does a World That Warms So Rapidly to 2 C Look Like?
OK. That was rough. But what I am about to do is much worse. I’m going to take a look at actual effects of what, to this point, has simply been a clinical analysis of the numbers. I’m going to do my best to answer the question — what does a world rapidly warming by 2 C over the next 22 years look like?
Ugly. Even more ugly than the numbers, in fact.
First, let’s take a look at rates of evaporation and precipitation. We know that, based on past research, the hydrological cycle increases by about 6% for each degree Celsius of temperature increase. So far, with about .8 C worth of warming, we’ve had about a 5% increase in the hydrological cycle. What this means is that evaporation rates increase by 5% and precipitation events, on average, increase by about 5%. But because weather is uneven, what this does is radically increase the frequency and amplitude of extreme weather. Droughts are more frequent and more severe. Deluges are more frequent and more severe.
(Program in which top climate scientists explain how global warming increases the intensity of evaporation and precipitation all while causing dangerous changes to the Jet Stream.)
At 2 C warming we can change this loading from a 5% increase in the hydrological cycle of evaporation and precipitation to a 12% increase. You think the droughts and deluges are bad now? Just imagine what would happen if the driver of that intensity more than doubled. What do you end up with then?
Now let’s look at something that is directly related to extreme weather — sea ice loss. In the current world, about .8 C worth of warming has resulted in about 3.2 C worth of warming in the polar regions. And this warming has resulted in a massive and visible decline of sea ice in which end summer volume values are up to 80% less than those seen during the late 1970s. This loss of sea ice has had severe effects on the Northern Hemisphere Jet Stream, both pulling it more toward the pole and resulting in high amplitude Jet Stream waves and local severe intensification of storm tracks. At 2 C worth of global warming, the Arctic heats up by around 7 C and the result is extended periods of ice free conditions during the summer and fall that last for weeks and months.
(Actual rate of sea ice loss vs IPCC model predictions. The most recent record low value achieved in 2012 is indicated by the dot. Image source: Assessment of Arctic Sea Ice/UCAR Report.)
The impacts to the Northern Hemisphere Jet Stream are ever more severe as are the impacts to Greenland ice sheet melt. Under such a situation we rapidly get into a weather scenario where screaming temperature differentials between the North Atlantic near Greenland and the warming tropics generate storms the likes of which we have never seen. Add in a 12% boost to the hydrological cycle and we get the potential for what Dr. James Hansen describes as “frontal storms the size of continents with the intensity of hurricanes.”
Greenland melt itself is much faster under 2 C of added heat and the ice sheets are in dangerous and rapid destabilization. It’s possible that the kick will be enough to double, triple, quadruple or more the current pace of sea level rise. Half foot or more per decade sea level rise rapidly becomes possible.
All this severe weather, the intense rain, the powerful wind storms and the intense droughts aren’t kind to crops. IPCC projects a 2% net loss in crop yields each decade going forward. But this is likely to be the lower bound of a more realistic 2-10 percent figure. Modern agriculture is hit very, very hard in the context of a rapidly changing climate, increasing rates of moisture loss from soil and moisture delivery through brief and epically intense storms.
The rapid jump to 2 C is also enough to put at risk a growing list of horrors including rapid ocean stratification and anoxia (essentially initiating a mass die off in the oceans), large methane and additional CO2 release from carbon stores in the Arctic, and the unlocking of dangerous ancient microbes from thawing ice, microbes for which current plants and animals do not have adequate immune defenses.
How do we avoid this?
In short, it might not be possible to avoid some or even all of these effects. But we may as well try. And this is what trying would look like.
First, we would rapidly reduce human greenhouse gas emissions to near zero. As this happens, we would probably want a global fleet of aircraft that spray sulfate particles into the lower atmosphere to make up for the loss of aerosols once produced by coal plants. Finally, we would need an array of atmospheric carbon capture techniques including forest growth and cutting, then sequestration of the carbon stored by wood in lakes or in underground repositories, chemical atmospheric carbon capture, and carbon capture of biomass emissions.
For safety, we would need to eventually reduce CO2 to less than 350 ppm, methane to less than 1,000 ppb, and eliminate emissions from other greenhouse gasses. A very tall order that would require the sharing of resources, heroic sacrifices by every human being on this Earth, and a global coordination and cooperation of nations not yet before seen. Something that is possible in theory but has not yet been witnessed in practice. A test to see if humankind is mature enough to ensure its own survival and the continuation of life and diversity on the only world we know. A tall order, indeed, but one we must at least attempt.