An isolated, 100-acre lake on the Canadian Arctic's Baffin Island is showing signs of warming that is unprecedented in 200,000 years of history due to human-caused climate change, according to a new report.
The multi-year study, led by scientists at the University of Colorado and published this week in the Proceedings of the National Academy of Sciences, is the latest to paint a picture of dramatic greenhouse warmth that is expected to warm the Arctic sooner than we think.
"We see clear evidence for warming in one of the most remote places on Earth at a time when the Arctic should be cooling because of natural processes," said lead author Yarrow Axford of the University of Colorado's Institute of Arctic and Alpine Research.
A natural cooling trend was observed in the Arctic during the last 8,000 years, cooling minus 0.36 degrees Fahrenheit every thousand years. That is, until 1950, when cold temperatures "abruptly declined."
The trouble is the cooling off was supposed to last another 4,000 years — a result of the ongoing "wobble" in the Earth's tilt that leaves the northern hemisphere about 0.6 million miles farther from the sun in summer and shrinks the intensity of the sunlight that strikes the Arctic.
The unnatural temperature boost on Baffin Island's remote Lake CF8 four millenia early is of particular concern for the researchers. It led to this sobering conclusion:
"The natural late-Holocene cooling trajectory has been preempted in the Arctic."
The culprit is the "human footprint," which is "beginning to overpower long-standing natural processes even at this remote site," they wrote.
To arrive at their numbers, researchers from five different institutions reconstructed the 30-foot-deep lake's climate record by examining sediment layers that have been buried beneath it. Some of the layers stretch back 200,000 years. The fossilized insects, algae and other geochemistry span two ice ages and three interglacial periods, and essentially date back to the beginning of humans on Earth.
That makes the CF8 sediment record unique in Greenland or the Canadian Arctic. It's the oldest lake-core sediment ever recovered by scientists by roughly 80,000 years.
The warming was detected in various ways. One of the biggest clues was the absence of the mosquito-like "midge." The insect flourishes in cooler temperatures and has been visible in the CF8 sediment for thousands of years. Around 1950, it began disappearing. Two of the midge species have vanished entirely.
Another red flag was the sudden increase in a certain lake algae in recent decades known to blossom in warmer conditions. Prior to the 20th century, it was rarely seen at Lake CF8.
The Baffin Island results are hardly an isolated case. According to the study:
"The timing of this shift coincides with widespread Arctic change, including warming attributed to a combination of anthropogenic forcings that are unprecedented in the Arctic system."
Indeed, the findings fall into step with several recent studies. In a major analysis published in the journal Science in September, a team of 30 scientists found that average temperatures in the Arctic in the past decade now rank higher than at any time since 1 B.C., courtesy of human-caused industrial emissions.
The study was based on more than a dozen lake sediment cores, as well as glacier ice and tree ring records. It is seen as some of the most definitive proof of human-caused global warming yet.
The Catlin Survey ice team just revealed its new Arctic data after taking 6,000 measurements on a 73-day, 280-mile trek that started on March 1. In a nutshell: The Arctic ice is thinning much faster than previously thought, and the Arctic and could be mostly ice-free in a decade and fully melted in 20 years in the summertime.
In its September study, the World Wildlife Federation (WWF) detailed what the warming Arctic means for the world. In sum, flooding could affect 25 percent of the world's population, and changing temperature and precipitation patterns in Europe and North America that will wreak havoc on agriculture, forestry and water supplies.
The Arctic region is considered a bellwether of global climate change. Scientists are hoping their studies ring loud among the world's biggest carbon-polluting nations before governments meet in Copenhagen in December to hammer out a Kyoto Protocol replacement targeted at stopping catastrophic warming.
But time is short. Another report released by WWF on October 20, called Climate Risk 2, says the world has but a half a decade window:
"The clock has continued to tick, inexorably counting down to the moment when, even if we do act, it may be too late to avoid runaway climate change. ... Climate Risk 2 models this point of no return. It shows that the constraints of our industries working in a market economy leave us with just five years before the speed of transition required puts a viable solution beyond our reach."