The tipping point where the planet becomes a 'Hothouse Earth' is terrifyingly real

"Hothouse Earth" is basically a self-sustaining engine of warming and carbon. Ummm...

Credit: PNAS

We are, suggest scientists publishing in the Proceedings of the National Academy of Sciences, just one degree (C) away from hitting a “tipping point” beyond which the planet has never experienced.


When average global temperatures reach 2 degrees C (4 degrees F) higher than pre-industrial times, we’ve hit that point. The problem is that we’re halfway there already

Beyond that temperature, our world will be in what the scientists are calling a 'Hothouse Earth' state, where climate change will be absolutely uncontrollable, and vast regions will be uninhabitable.


Flames from the Rocky Fire approach a house on July 31, 2015 in Lower Lake, California.  (Photo by Justin Sullivan/Getty Images)

"We note that the Earth has never in its history had a quasi-stable state that is around 2C warmer than the preindustrial and suggest that there is substantial risk that the system, itself, will 'want' to continue warming because of all of these other processes—even if we stop emissions," study author Katherine Richardson from the University of Copenhagen told The Guardian.

What happens after that threshold is reached is that Earth’s feedback loop, which normally cools the planet and offsets some of the human activity, will actually fail. Or, rather, it will reverse. More carbon is fed into our atmosphere as rainforests dry up and permafrost melts, releasing methane. That self-reinforces the warming effects we’re already seeing. And as more rainforests evaporate, Arctic permafrost melts, ice caps at both poles of the planet disappear, and coral reefs die off, even more carbon is released into the atmosphere, adding yet more fuel to the dysfunctional system. Basically, it means Earth itself becomes a primary source of greenhouse gas emissions. It will come to a point where nothing humans can do will help mitigate the changes. 


Ice calves at the Perito Moreno glacier in Los Glaciares National Park, part of the Southern Patagonian Ice Field, the third largest ice field in the world, on November 27, 2015 in Santa Cruz Province, Argentina. (Photo by Mario Tama/Getty Images)

While the scientists who penned the article are stating this is not yet a theory, but rather an extension of existing scientific studies providing more food for thought, predictions include:

  • Sea levels increasing by 33 to 300 feet (10 to 60 meters) 
  • Temperatures increasing by 7 to 9 degrees F (4 to 5 C) worldwide
  • Humans, unable to live near the equator, forced to migrate to both the North and South poles to survive

“I do hope we are wrong, but as scientists, we have a responsibility to explore whether this is real,” said Johan Rockström, executive director of the Stockholm Resilience Centre and one of the study authors. “We need to know now. It’s so urgent. This is one of the most existential questions in science.”

If the magic (?) number of 2 degrees sounds familiar, it should; that’s the target (ideally, 1.5 degrees) that the Paris Agreement, originally signed by 179 countries (with the United States pulling out of last year), spelled out for a reduction in carbon emissions this century. 

However, even if the world ceased all carbon emissions by 2050, that’s still not enough to stop the feedback loop from cascading into the nightmare scenario outlined in the paper:

“If the [2 degree] threshold is crossed, the resulting trajectory would likely cause serious disruptions to ecosystems, society, and economies.” 

Also, the event would pose "severe risks for health, economies, political stability, and ultimately, the habitability of the planet for humans.”

Think this will make anybody sit up and take notice?

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It looks like a busy hurricane season ahead. Probably.

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  • Before the hurricane season even started in 2020, Arthur and Bertha had already blown through, and Cristobal may be brewing right now.
  • Weather forecasters see signs of a rough season ahead, with just a couple of reasons why maybe not.
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Welcome to Hurricane Season 2020. 2020, of course, scoffs at this calendric event much as it has everything else that's normal — meteorologists have already used up the year's A and B storm names before we even got here. And while early storms don't necessarily mean a bruising season ahead, forecasters expect an active season this year. Maybe storms will blow away the murder hornets and 13-year locusts we had planned.

NOAA expects a busy season

According to NOAA's Climate Prediction Center, an agency of the National Weather Service, there's a 60 percent chance that we're embarking upon a season with more storms than normal. There does, however, remain a 30 percent it'll be normal. Better than usual? Unlikely: Just a 10 percent chance.

Where a normal hurricane season has an average of 12 named storms, 6 of which become hurricanes and 3 of which are major hurricanes, the Climate Prediction Center reckons we're on track for 13 to 29 storms, 6 to 10 of which will become hurricanes, and 3 to 6 of these will be category 3, 4, or 5, packing winds of 111 mph or higher.

What has forecasters concerned are two factors in particular.

This year's El Niño ("Little Boy") looks to be more of a La Niña ("Little Girl"). The two conditions are part of what's called the El Niño-Southern Oscillation (ENSO) cycle, which describes temperature fluctuations between the ocean and atmosphere in the east-central Equatorial Pacific. With an El Niño, waters in the Pacific are unusually warm, whereas a La Niña means unusually cool waters. NOAA says that an El Niño can suppress hurricane formation in the Atlantic, and this year that mitigating effect is unlikely to be present.

Second, current conditions in the Atlantic and Caribbean suggest a fertile hurricane environment:

  • The ocean there is warmer than usual.
  • There's reduced vertical wind shear.
  • Atlantic tropical trade winds are weak.
  • There have been strong West African monsoons this year.

Here's NOAA's video laying out their forecast:

But wait.

ArsTechnica spoke to hurricane scientist Phil Klotzbach, who agrees generally with NOAA, saying, "All in all, signs are certainly pointing towards an active season." Still, he notes a couple of signals that contradict that worrying outlook.

First off, Klotzbach notes that the surest sign of a rough hurricane season is when its earliest storms form in the deep tropics south of 25°N and east of the Lesser Antilles. "When you get storm formations here prior to June 1, it's typically a harbinger of an extremely active season." Fortunately, this year's hurricanes Arthur and Bertha, as well as the maybe-imminent Cristobal, formed outside this region. So there's that.

Second, Klotzbach notes that the correlation between early storm activity and a season's number of storms and intensities, is actually slightly negative. So while statistical connections aren't strongly predictive, there's at least some reason to think these early storms may augur an easy season ahead.

Image source: NOAA

Batten down the hatches early

If 2020's taught us anything, it's how to juggle multiple crises at once, and layering an active hurricane season on top of SARS-CoV-2 — not to mention everything else — poses a special challenge. Warns Treasury Secretary Wilbur Ross, "As Americans focus their attention on a safe and healthy reopening of our country, it remains critically important that we also remember to make the necessary preparations for the upcoming hurricane season." If, as many medical experts expect, we're forced back into quarantine by additional coronavirus waves, the oceanic waves slamming against our shores will best be met by storm preparations put in place in a less last-minute fashion than usual.

Ross adds, "Just as in years past, NOAA experts will stay ahead of developing hurricanes and tropical storms and provide the forecasts and warnings we depend on to stay safe."

Let's hope this, at least, can be counted on in this crazy year.

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