From news.com.au this “stunning” development citing lake sediment and some midges “proves” everything. Glad that’s settled. See thoughts at the end.
This is the title of the story at news.com.au, link to story here
But here is the University of Colorado press release that started it all. Note that in no place in the release do they use the word “proof”.
Arctic Lake Sediment Record Shows Warming, Unique Ecological Changes in Recent Decades
October 19, 2009
An analysis of sediment cores indicates that biological and chemical changes occurring at a remote Arctic lake are unprecedented over the past 200,000 years and likely are the result of human-caused climate change, according to a new study led by the University of Colorado at Boulder.
While environmental changes at the lake over the past millennia have been shown to be tightly linked with natural causes of climate change — like periodic, well-understood wobbles in Earth’s orbit — changes seen in the sediment cores since about 1950 indicate expected climate cooling is being overridden by human activity like greenhouse gas emissions. The research team reconstructed past climate and environmental changes at the lake on Baffin Island using indicators that included algae, fossil insects and geochemistry preserved in sediment cores that extend back 200,000 years.
“The past few decades have been unique in the past 200,000 years in terms of the changes we see in the biology and chemistry recorded in the cores,” said lead study author Yarrow Axford of CU-Boulder’s Institute of Arctic and Alpine Research. “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.”
The study was published Oct. 19 in the Proceedings of the National Academy of Sciences. The study included researchers from CU-Boulder, the State University of New York’s University at Buffalo, the University of Alberta, the University of Massachusetts and Queen’s University in Kingston, Ontario.
The sediment cores were extracted from the bottom of a roughly 100-acre, 30-foot-deep lake near the village of Clyde River on the east coast of Baffin Island, which is several hundred miles west of Greenland. The lake sediment cores go back in time 80,000 years beyond the oldest reliable ice cores from Greenland and capture the environmental conditions of two previous ice ages and three interglacial periods.
The sediment cores showed that several types of mosquito-like midges that flourish in very cold climates have been abundant at the lake for the past several thousand years. But the cold-adapted midge species abruptly began declining in about 1950, matching their lowest abundances of the last 200,000 years. Two of the midge species adapted to the coldest temperatures have completely disappeared from the lake region, said Axford.
In addition, a species of diatom, a lake algae that was relatively rare at the site before the 20th century, has undergone unprecedented increases in recent decades, possibly in response to declining ice cover on the Baffin Island lake.
“Our results show that the human footprint is overpowering long-standing natural processes even in remote Arctic regions,” said co-author John Smol of Queen’s University. “This historical record shows that we are dramatically affecting the ecosystems on which we depend.”
The ancient lake sediment cores are the oldest ever recovered from glaciated parts of Canada or Greenland. Massive ice sheets during ice ages generally scour the underlying bedrock and remove previous sediments.
“What is unique about these sediment cores is that even though glaciers covered this lake, for various reasons they did not erode it,” said study co-author Jason Briner of the University at Buffalo. The result is that we have a really long sequence of sediment that has survived Arctic glaciations.”
Axford emphasized the multiyear research project required expertise from each of the five institutions involved in the PNAS study. “This was a team effort all the way around, and each of the institutions has a unique set of skills that allowed us to carry out this study,” she said. “We needed people who understood algae, insects, glaciers and geochemistry, not to mention how to drive snowmobiles and extract the cores.”
The study was funded by the National Science Foundation, the Natural Sciences and Engineering Research Council of Canada and the Geological Society of America.
A study published in Science magazine last month that involved CU-Boulder researchers and reconstructed past temperatures in the Arctic using ice cores, tree rings and lake sediments concluded that recent warming around the Arctic is overriding a cooling trend caused by Earth’s periodic wobble. Earth is now about 0.6 million miles further from the sun during the Northern Hemisphere summer solstice than it was in 1 B.C. — a trend that has caused overall cooling in the Arctic until recently.
INSTAAR researcher and CU-Boulder geological sciences Professor Gifford Miller was a co-author on both the PNAS study and the recent Science study.
A scientist on a mailing list I subscribe to put it in perspective this way:
1. “several types of mosquito-like midges that for many thousands of years thrived in cold climate surrounding the lake suddenly began declining at around 1950″ — Have they accounted for the use of DDT, then? Seems to me that DDT on Baffin Island could have been very popular among trappers and the military in the 50s. Possibly pertinent too:
- DDT and its breakdown products are transported from warmer regions of the world to the Arctic by the phenomenon of global distillation, where they then accumulate in the region’s food web
Thus there might be a human impact on this parameter, but of another kind.
Beyond that, though, if the authors are suggesting that CO2 has caused a mosquito or midge shortage up north, they should consult caribou herds, whose route of wandering is traceable to wind direction, so desperate are these animals to escape the floating bloodsuckers.
- In the Canadian Arctic, researchers who bared their arms, legs, and torsos in an experiment reported as many as 9,000 [mosquito] bites per minute.
Who knows, then? Changing wind patterns and a consequent shift of caribou migration (the supporting host) or DDT usage might account for the decline of midge bodies in this particular study of Ayr Lake. But CO2?
2. “The Earth is now some 600,000 miles (966,000 kilometers) further from the sun during the Northern Hemisphere summer solstice than it was at the time of Jesus Christ” — A sad example of allegation that’s already become a repeated “fact” simply because no one’s bothered to investigate it. I have, and find no indication that this million km claim is true.
Just a note on DDT from Wikipedia:
First synthesized in 1874, DDT’s insecticidal properties were not discovered until 1939. In the second half of World War II, it was used with great effect to control mosquitoes spreading malaria and lice transmitting typhus among civilians and troops, resulting in dramatic reductions in the incidence of both diseases. The Swiss chemist Paul Hermann Müller was awarded the Nobel Prize in Physiology or Medicine in 1948 “for his discovery of the high efficiency of DDT as a contact poison against several arthropods.” After the war, DDT was made available for use as an agricultural insecticide, and soon its production and use skyrocketed.
Here’ s a 2008 study on DDT in penguins that sums it up pretty well:
POPs (Persistent organic pollutants) accumulate in the Antarctic and Arctic via repeated cycles of evaporation and condensation as they move poleward through the atmosphere from the tropical and temperate zones where most are released.
Or how about this one:
2005 TORONTO (CP) – Seabird droppings are leaving more than a foul mess in the Arctic – they’re contaminating northern lakes and ponds with extremely high levels of mercury and DDT, Canadian researchers have found.
Concentrations of the chemicals were found to be as much as 60 times higher in bodies of water on Devon Island, Nunavut, than in other Arctic areas, says a study to be published Friday in the journal Science.
No, no it couldn’t be DDT killing those midges, it has to be global warming since 1950.
Journalism is dead, science may not be far behind.