New dire climate change model

Research by Canadian scientists recently published in Nature Climate Change reveals a world climate in the future that rivals the world climate of 56 to 52 million years ago during the Eocene Era.

In a May 23 article for National Geographic Magazine, Marianne Lavelle wrote that previous bleak predictions of climate change for the end of this century offered hope that global warming would eventually slow down. “But a new study ... snuffs out such hope, projecting temperatures that rise lockstep with carbon emissions until the last drop of oil and lumps of coal are used up.”

The Canadian scientists are now predicting that global temperatures will rise 8°C (14.4°C)  by the year 2300 if all the planet’s fossil fuel resources are burned. In the Arctic, the temperature rise would be by 17°C (30.6°F) — most scientists agree that temperatures in the Arctic are rising at twice the rate as the mid-latitudes as a result of the build-up of greenhouse gases.

The Paris talks of a few months ago called for global temperature cap of 2°C (3.8°F). That limit would be far exceeded by the prediction made by the Canadians.

It’s a dire prediction that has a much higher temperature than earlier climate change forecasts.

According to the scientists, if the temperatures become a reality, greenhouse gases will transform the Earth into a place where food is scarce, parts of the planet are uninhabitable for humans and many species of plants and animals will be wiped out.

“It would be as unrecognizable to us as a fully-glaciated world, Myles Allen, head of a climate dynamics group at the University of Oxford in England, told Lavelle.

Allen was not involved in the new study, but his research focuses on carbon’s accumulative impact on climate.

Allen told Lavelle that it took less warming, 6°C (10.6°F) to bring the world out of the last Ice Age. “That’s the profundity of the change we’re talking about,” he added.

Fifty-three to 52 million years ago, Canada’s Arctic possessed lush mixed conifer (cedar and redwoods)-broadleaf (alder, birch and walnut) rain forests where alligators, turtles and fish swam in freshwater swamps and tortoises roamed the land. Mammals included primates, tapirs, brontheres (rhinoceros-like ungulates) and hippo-like Coryphodom.

At the time, the forested landscape were somewhat similar to the floodplain forests of today’s southwestern United States.

Winter temperatures during the Eocene in Canada’s Arctic were just above freezing, while summer-time temperatures hovered around 20°C.

At the time, the Arctic regions where such fossils were found were just a few degrees further south of their present latitudes, but still within the Arctic Circle. As a result, these forests communities experienced months of continuous sunlight, twilight and darkness, similar to today’s conditions.

Jaelyn Eberle, a geological sciences professor at the University of Colorado, when analyzing the oxygen isotope ratios from the enamel and bones of fossils of mammals, turtles and fish found in Canada’s High Arctic in 2010, said the “data set for the early Eocene High Arctic ... certainly explains how alligators and giant turtles could live on Ellesmere Island 52 to 53 million years ago” (CTV News).

The Colorado researchers found that Eocene alligators could withstand slightly cooler winters than their present counterparts, which isn’t really all that surprising since alligators are extremely adaptable creatures. But such reptiles cannot survive today’s bitterly cold Arctic climate.

Quite different from today is that during the millenium leading to and during the Eocene, there were no Arctic and Antarctic ice caps when greenhouse gas warming brought semi-tropical conditions to Canada’s North.

“In the future, warming will melt ice caps, which will expose bare ground, increasing heat absorption at high latitudes, and cause more warming,” Scott Wing, the Smithsonian Institute’s curator of fossil plants, told Lavelle.

When the Poles melt, sea levels will rise and that would mean the upheaval of coastal populations, which make up more than 40 per cent of humanity.

Lavelle wrote that the study by the Canadian scientists predicts that precipitation would quadruple in the tropical Pacific, while it would be reduced by up to a third in the Americas and a factor of two  for parts of Australia, the Mediterranean, southern Africa and the Amazon.

Lavelle quoted Allen as saying that not only could tropical rainforests systems collapse, but drought in southern Europe and the U.S. would be “completely catastrophic for agriculture.”

While wealthy nations may be able to maintain their food supplies, other places such as southern Africa would not.

“A lot of people would have to leave, or a lot of people would die,” said Allen.

Eocene mammals, reptiles and fish also had time to evolve and adapt to their environment, but such would not be the case for the majority of today’s Arctic animals and other species. The period of extreme warming during the Eocene was triggered by rising greenhouse gases over a 10,000-year period.

A timeframe of a mere 200 to 300 years of extreme greenhouse gases rising and upping the Earth’s temperatures —which is an instant in geological time — would prevent adaptation and contribute to a mass extinction of species.

The Canadian study is based on a new modelling which attempts to answer questions left unanswered by the Intergovernmental Panel on Climate Change (IPCC). “The IPCC’s worst-case scenario only charts warming up to two trillion tonnes of cumulative added carbon in 2100,” wrote Lavelle. “In the new study, (Katazyna) Tokarska (a researcher at the University of British Columbia) and her colleagues asked what would happen if all known and recoverable fossil fuel resources were used.”

The IPCC predicted a temperature rise of 2.6°C (4.8°F) by the year 2100.

“Tokarska and her team say that these past projections failed to include the complex give-and-take of carbon on Earth. Most importantly, oceans — like a saturated sponge — lose their ability to absorb more heat and carbon, leaving it nowhere to go but the atmosphere.”

Matthew Huber, an earth scientist at Purdue and the University of New Hampshire, told Lavelle that fixation on the year 2100 “is unhealthy and ignores the large risks that become apparent when thinking on longer time scales and with a more complete treatment of real physical and biological processes.”

The greatest problem facing the world is that until cheaper alternatives are found or some effective means of capturing and storing carbon is found, the reliance on fossil fuels will continue well into the next century. Keeping fossil fuels in the ground, as some suggest, is not a viable option at this stage.

But as the new study suggests, continuing the present state of affairs dooms the world of the not-to-distant future.