Prominent Climate Scientists Say Boulder-Hurling Megawaves Are Decades Away

Prominent Climate Scientists Say Boulder-Hurling Megawaves Are Decades Away

Over winter, pioneering climate scientist James Hansen and his colleagues penned an apocalyptic study predicting that the deadliest consequences of climate change will be felt within decades. That paper precipitated a raucous debate, but now, it's been accepted for publication, heralding a sea shift in attitudes toward climate studies that make dire and outlandish predictions. And we're not kidding when we say dire. The paper forecasts collapsing ice sheets, epic superstorms, even mega-boulder-hurling mega-waves. (If you don't believe me, check out the entire subsection devoted to said mega-boulders.) Most significantly, the study predicts that we'll begin to feel these climate consequences within a few decades rather than a few centuries. Also, that the 2 degree Celsius climate warming benchmark bandied about by scientists and policymakers is extremely dangerous.

In a nutshell, here's how all of this works. It starts with melting of the Greenland and Antarctic ice sheets, something we're already beginning to see. As cool, fresh meltwater pours off of the ice sheets and into the ocean, it creates a stratified layer that floats atop warmer, denser ocean water. This, in turn, disrupts the ocean's normal "overturning circulation" pattern, which mixes the entire water column and allows heat energy accumulated at depth to be redistributed to the surface.

Trapped in the deeper layers of the ocean, warm waters eat away at the bottoms of the ice sheets, leading to more rapid melting and eventually, catastrophic destabilisation. This causes even more freshwater to enter the surface ocean, resulting in more sea level rise (several meters over the course of the century, Hansen predicts) and more thermal stratification. Suddenly, we've got ourselves in a nasty feedback loop that results in the complete shutdown of major ocean energy currents.

A shutdown of the North Atlantic Overturning Circulation, which brings heat energy to western Europe and eastern North America, results in regional cooling, even as global warming heats up the tropics. The growing temperature differential between mid-latitudes and the equator drives some of the more apocalyptic climate change consequences discussed in the paper, including more frequent and intense superstorms, accompanied by waves capable of tossing hundred-tonne boulders into the air.

Strictly speaking, the idea isn't new. In fact, Hansen's predictions are modelled after events that geologists and paleoclimate researchers believe took place during the Eemian, a period some 80,000 to 130,000 years ago when the Earth was only slightly warmer but sea levels were 6 to 9 meters higher than they are today. It's also — loosely speaking — the climate disaster scenario that inspired The Day After Tomorrow.

Hansen's paper was first released online and publicised over winter, before the peer review process was complete. A high profile debate ensued, in which Hansen and his co-authors were criticised for sharing their findings with journalists before the study had gone through academic review. Hansen, a former NASA scientist who famously brought climate change to the public's attention during a congressional testimony in 1988, has become a political activist in recent years, leading some in the scientific community to worry that he's lost his objectivity. While he's not the only climate scientist frustrated with glacially slow pace of political action on climate change, scientists who turn to activism risk opening the broader community to criticism.

Even now that Hansen's paper has been vetted and accepted for publication, not all climate scientists are on board with its conclusions. Speaking to the Washington Post, two Penn State scientists criticised the paper's weak ice sheet physics, and said the predicted amounts of meltwater seem "unphysically large".

On the other hand, even if this paper's forecast is extreme — and it is — the fact remains it's a scenario that the scientific community is willing to entertain. And that should have us all worried. Because several metres of sea level rise, accompanied by extreme and dangerous weather, would be a catastrophe for human society. As the paper dramatically concludes, "It is not difficult to imagine that conflicts arising from forced migrations and economic collapse might make the planet ungovernable, threatening the fabric of civilisation."

"It is far from certain that the results contended [in this study] shall match what will happen in the real-world," writes Peter Thorne, a climate scientist at the National University of Ireland Maynooth and a reviewer for Hansen's paper. "At the same time, however, it would be foolish in extremis to discount this out of hand as a possibility of what shall occur."

[Atmospheric Chemistry and Physics via New York Times]

Image: Deep Impact


Comments

    The climate science community seems to be fairly conserved with their models and estimates, the IPCC for example is notoriously conservative. Some may see this as good science, not including certain data in your models that you can't accurately simulate, even tho you know it will have a huge impact on future climate. I think this "good" conservative science approach might be doing us a disservice however, and we need more respected scientists to come forward to tell us how bad things will really be, because it's really the only thing that will drive home the point of how bad this will get if we don't start tackling climate change seriously.

      I understand what you mean, but that may also have a negative impact. Making claims, especially from science, without strong evidence can lead to false predictions, as certainty and some variables are still unknown. If you see some predictions not coming to fulfillment, people may not heed the growing danger? I am by no means a denier, but science should always tread carefully when theory is stronger than observation. Our rise in technology got us into this shit, but we need stronger fiscal commitment, if there is any hope of using science and technology to get us out of it. Atmospheric carbon collection, alternate power supply etc, are our only hope, we are past the point of no return.

      edit: I couldn't spell heed...

      Last edited 24/03/16 8:25 pm

    So what effect will shutting down the North Atlantic overturning circulation have... Along with the other polar circulations... Regional cooling... Which results in what... Colder poles... Which results in what... More ice and snow at the poles...
    Our planet has been hotter than now, and colder than records exist.. Our planet is a self balancing climate, it just takes many decades, and we've only been looking at a statistically manipulated set of observations from the last 3-4 decades.
    The climate change scientists have proven their case, so let's sack them all and use the money that is now wasted on producing further proof to an ready proven fact and spend it on "climate finding research" that will actually help our kids.

    I think people should Google "James Hansen" and they'll quickly come to a conclusion they don't need to worry about his predictions or take this article seriously.. Also look at the raw data for sea level change and you'll see catastrophic sea level change isn't supported by measured data. For example our own Fort Denison in Sydney Harbour has reliable records over the last 128 years and over the last century the rise has been 6.5 cm. The rate of sea level rise measured there has also been decreasing over the last 50 years not increasing. I'm very disappointed that Gizmodo published this alarmist article.

      Would you believe sea level doesn't rise uniformly across the planet, and can rise more in some parts of the planet than others? This is due to certain areas of the planet having more mass/gravity than others, therefore attracting more water... and maybe temperatures in those locations also cause water to expand locally... but I'm just guessing that. I'm not here to debate you, but thought i'd point it out if you didn't know, can be a lot to get your head around.

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