New Method Forecasts Near Term Climate Change; Results Not Good

Illustration from Popular Mechanics, March 1912 (source). Who knew we'd be in trouble? Everyone who bothered to look.

by Gaius Publius

This is more climate news roundup than anything more deeply analytical. The changes we're seeing, which by now almost everyone on the planet is noticing, are here to stay. Whatever natural variability people hoped might boomerang from these hot years down to the average of the last 20 ... doesn't exist.

We appear to have crossed a line, at least in the near term; the hot years will be here for a while. From Agence France Presse:

Brace for extra-warm weather through 2022: Study

PARIS (AFP) - Manmade global warming and a natural surge in Earth's surface temperature will join forces to make the next five years exceptionally hot, according to a study published on Tuesday (Aug 14).

The double whammy of climate change and so-called natural variability more than doubles the likelihood of "extreme warm events" in ocean surface waters, creating a dangerous breeding ground for hurricanes and typhoons, they reported in Nature Communications.

"This warm phase is reinforcing long-term climate change," lead author Florian Sevellec, a climate scientist at the University of Brest in France, told AFP.

"This particular phase is expected to continue for at least five years."

What's notable about this study is the new methodology, which separates the "noise" of natural climate variability from the "forced trend" of global warming itself. From the Abstract (emphasis added):

A novel probabilistic forecast system predicting anomalously warm 2018-2022 reinforcing the long-term global warming trend

In a changing climate, there is an ever-increasing societal demand for accurate and reliable interannual predictions. Accurate and reliable interannual predictions of global temperatures are key for determining the regional climate change impacts that scale with global temperature, such as precipitation extremes, severe droughts, or intense hurricane activity, for instance. However, the chaotic nature of the climate system limits prediction accuracy on such timescales. Here we develop a novel method to predict global-mean surface air temperature and sea surface temperature, based on transfer operators, which allows, by-design, probabilistic forecasts.[...]

The language is dense and academic, so I've highlighted key ideas. "Interannual" means year-to-year predictions, as opposed to century-length predictions. The reason is that there are a lot of chaotic inputs — natural variability from various sources — in addition to the relentless march of the greenhouse effect.

On timescales of 100 years, the chaotic variability (the "noise") gets smoothed out and the greenhouse trend is more visible. The problem is, people alive to day want to know what's going to happen to them in a year or two. So the authors have devised a novel method to predict air and sea surface temperature that factors out that "noise."

The Abstract states that this probabilistic method of prediction was tested against the so-called "pause" that occurred after the El Niño-spike year of 1998 and it passed; that is, its analysis predicted the pause from the data available.

The Abstract then says we're pretty much in for a ride for the next five years:

The post-1998 global warming hiatus is well predicted. For 2018–2022, the probabilistic forecast indicates a warmer than normal period, with respect to the forced trend [the global warming input]. This will temporarily reinforce the long-term global warming trend. The coming warm period is associated with an increased likelihood of intense to extreme temperatures.

The fact that these calculations can be done on a laptop instead of a Cray supercomputer means real-time analysis becomes more and more possible: "The important numerical efficiency of the method (a few hundredths of a second on a laptop) opens the possibility for real-time probabilistic predictions carried out on personal mobile devices."

The good news: People may become motivated a lot sooner than if the disaster just crept up on them. We'll see if it works out that way. Me, I'm hopeful.

Hothouse Earth

Next, another recent study looks at the likelihood of tipping points sending the planet into a state they've cleverly dubbed "Hothouse Earth":

This summer people have been suffering and dying because of heat waves and wildfires in many parts of the world. The past three years were the warmest ever recorded, and 2018 is likely to follow suit. What we do in the next 10-20 years will determine whether our planet remains hospitable to human life or slides down an irreversible path to what scientists in a major new study call “Hothouse Earth” conditions.

Hothouse Earth is an apocalyptic nightmare where the global average temperatures is 4 to 5 degrees Celsius higher (with regions like the Arctic averaging 10 degrees C higher) than today, according to the study, “Trajectories of the Earth System in the Anthropocene,” published Monday [August 6] in the Proceedings of the National Academy of Sciences. Sea levels would eventually be 10-60 meters higher as much of the world’s ice melts. In these conditions, large parts of the Earth would be uninhabitable.

These are the key paragraphs from the study itself (linked citations at the source; my emphasis):

The Anthropocene represents the beginning of a very rapid human-driven trajectory of the Earth System away from the glacial–interglacial limit cycle toward new, hotter climatic conditions and a profoundly different biosphere (2, 8, 9) (SI Appendix). The current position, at over 1 °C above a preindustrial baseline (10), is nearing the upper envelope of interglacial conditions over the past 1.2 million years (SI Appendix, Table S1). More importantly, the rapid trajectory of the climate system over the past half-century along with technological lock in and socioeconomic inertia in human systems commit the climate system to conditions beyond the envelope of past interglacial conditions. We, therefore, suggest that the Earth System may already have passed one “fork in the road” of potential pathways, a bifurcation (near A in Fig. 1) taking the Earth System out of the next glaciation cycle (11).

Translation: The day of the ice age is gone for a good long while.

More importantly, the rapid trajectory of the climate system over the past half-century along with technological lock in and socioeconomic inertia in human systems commit the climate system to conditions beyond the envelope of past interglacial conditions. We, therefore, suggest that the Earth System may already have passed one “fork in the road” of potential pathways, a bifurcation (near A in Fig. 1) taking the Earth System out of the next glaciation cycle (11).

Note the twin causes the authors identify above — "technological lock in" and "socioeconomic inertia in human systems." This is science-speak for "the CO2 we've emitted already" and "letting ourselves be ruled by people who won't let us act."

What's new about this study is the wide range of feedbacks it studies. The chart below gives a good indication of that range. Yellow indicates which systems will be affected first; orange-coded systems will be affected next; then red-coded systems.

Fig 3. Global map of potential tipping cascades. The individual tipping elements are color-coded according to estimated thresholds in global average surface temperature (tipping points) (12, 34). Arrows show the potential interactions among the tipping elements based on expert elicitation that could generate cascades. Note that, although the risk for tipping (loss of) the East Antarctic Ice Sheet is proposed at >5 °C, some marine-based sectors in East Antarctica may be vulnerable at lower temperatures (35–38). [click to enlarge]

We're already seeing major disruptions in the yellow systems — Greenland and West Antarctic ice sheets, Arctic sea ice, glaciers and coral reefs. Nothing new there, except that we may be ahead of schedule.

What's alarming is disruption to one of the orange-coded systems — the jet stream. It's fragmenting already. Note the arrow from Arctic ice collapse to the jet stream, showing causality. Arctic ice collapse may be well ahead of schedule, disrupting the jet stream earlier than the authors' projected schedule indicates.

Also coded orange is the Thermohaline circulation — the Atlantic Gulf Stream and all of the other important circulating oceanic water currents. The Gulf Stream keeps northern Europe from freezing like eastern Canada in the winter. If the Gulf Stream weakens or fails to move as far north as it currently does, Europe will become an exit point for climate refugees, not an entry point.

The good news here is the same as the good news above: The faster a collapse begins to be apparent, the more likely it is that people will react early in the process and mitigate it. My parallel here is the Great Depression, which mobilized people in great and united numbers behind FDR and the New Deal.

In that respect, the "ahead of schedule" systems noted above should make things apparent to the many — unlike polar bears on ice flows, which apparently made things apparent only to the few.

Electric Air Travel

Finally, some better good news. Last year I wrote that "All-electric air travel is not an impossible dream," that air travel, in other words, doesn't have to be tethered to oil and gas. There are developments on that front:

The electric plane startup backed by Boeing and JetBlue just sold 100 planes and the deal could spark a new era of air travel in the US

...Zunum, the electric plane startup backed by JetBlue Technology Ventures and Boeing HorizonX, revealed that JetSuite will take up to 100 planes with deliveries expected to commence in 2022. The financial terms of the deal have not been released.

Granted, 2022 is pretty late in the game for converting our air fleet, and I'll have more to say in a bit about the need for energy rationing in order to convert the whole economy. (For a hint about the need for rationing, see this excellent long-form comic about Buckminster Fuller's thought about energy and energy source conversion.) Still, it's good to see doors that seemed locked start to open up.

GP