Amazon Rain Forest Drought, Arctic Sea Ice Melt, Boreal Forest Destruction, Geneticist Andrea Manica, Greenland Ice Quakes, Greenland Ice Sheet Melt, Hans Joachim Schellnhuber, Professor Tim Lenton, Runaway Climate Change, Tipping Elements in the Climate System
Coronal Mass Ejection from August 31, 2012. And the associated 4096×4096 (!) video.
What force, more than anything else, has regulated the evolution and expansion of mankind throughout history? A new study with climate models by geneticist Andrea Manica at the University of Cambridge, UK, and his colleagues shows how sensitive the human species has been to climate over the past 120,000 years and continues to be to the present day. The rise and fall of ice sheets and sea levels and the desertification of continents acted as road blocks to control the migration and settlement of humans across the planet.
…To see just how sensitive our species has been to changes in climate over the ages, Manica ran the model several times, varying the strength of climate’s effect on populations.
In parallel, he also modelled the history of human genetic variation, and compared that with real data on the genetic makeup of modern populations. Strikingly, he was only able to reproduce the known timings of migrations, and the real-world genetic data, if the human populations in his model were highly sensitive to the climate.
It’s the first time anyone has been able to explore climate’s power to facilitate human expansion, says Rick Potts of the Smithsonian National Museum of Natural History in Washington DC. “The study fills in many of the links that have only been assumed or guessed at,” he says…
…Stewart has proposed that earlier bouts of climate change helped the many hominin species to evolve, by forcing them into isolated refuges where they evolved separately (Science, doi.org/jcz). If that’s correct, climate has been determining our fate for even longer than Manica’s model suggests.
Manica argues that modern civilisation is still highly dependent on the climate. Many societies have declined or collapsed when faced with climate change, for example.
While agriculture produces more food than hunting and gathering, and so supports more people, ultimately climate’s effect on food production still limits our population. “We are very much governed by climate,” he says.
With the discovery of oil, coal, and other fossil fuels we were able to vastly increase our numbers. Our entire transportation system, industrialized agricultural system, globalized economy of trade, and modern medical system would not exist without fossil fuels. Even so, humanity could have dealt with the painful problem of peak oil by powering down to a less energy intensive way of life, but something much more insidious developed which would throw modern civilization for a loop. Professor Tim Lenton and Hans Joachim Schellnhuber wrote a paper in 2007 identifying 9 specific tipping elements for the Earth’s climate:
Click to Enlarge…
1.) The Arctic sea ice is considered a “highly sensitive” tipping point with low uncertainty and is expected to disappear completely in summer within a decade, leaving behind open and dark waters which will absorb more of the sun’s heat that once was reflected by white ice.
In figure below, global emissions cause warming, especially in the Arctic, where warming is further accelerated by feedbacks, in particular sea ice loss and methane releases, threatening to lead to runaway global warming.
From the following graph, you can see Lenton’s and Schellnhuber’s tipping points (8 of 14) which are sensitive(yellow/red) to just a few degrees of warming:
Several positive feedbacks have been identified within the first tipping point of disappearing Arctic sea ice:
There are at least three positive feedbacks working together to reinforce one another – and now a fourth on salinity:
- The albedo flip effect as sea ice is replaced by open water absorbing more sunlight, warming and melting more sea ice.
- As the sea ice gets very thin, it is liable to break up easily and get blown into open water where it will melt more easily.
- The open warmer water is allowing increased strength of storms, which break up the ice to make for more open water.
- The storms are churning up the sea to a depth of 500 metres, producing salinity at the surface that will mean slower ice formation in winter and more open water next year.
These feedbacks are dangerous for methane. AMEG has been warning that, as the sea ice retreats, storms will warm the sea bed, leading to further release of methane. In ESAS, we only need mixing to a depth of 50 metres – so a storm capable of mixing to 500 metres will really stir things up.
Another feedback is the pollution and soot resultant from increased shipping traffic, oil drilling activity, and other exploitive ventures by our ravenous and wrong-headed culture. Like arsonists taking pleasure in their destructive activities, industrial civilization simply throws more fuel into the bonfire of anthropogenic climate chaos. You can see plainly from the current Arctic resource grab that “THE MARKET” is a soulless, nihilistic, and sapient-less entity with a one-track mind of commodification and exploitation.
2.) The Greenland ice sheet is considered a “highly sensitive” tipping point with low uncertainty and a decay time of approximately 300 years as cycles of degradation and regrowth tip toward melting. A rise in sea levels of more than 20 feet is estimated from the melting of the Greenland ice sheet.
As with other underestimations of mankind’s effect on nature, we have done the same with the destruction of the Greenland ice sheet:
The Greenland ice sheet is likely to be more vulnerable to global warming than previously thought. The temperature threshold for melting the ice sheet completely is in the range of 0.8 to 3.2 degrees Celsius of global warming, with a best estimate of 1.6 degrees above pre-industrial levels, shows a new study by scientists from the Potsdam Institute for Climate Impact Research (PIK) and the Universidad Complutense de Madrid. Today, already 0.8 degrees of global warming has been observed. Substantial melting of land ice could contribute to long-term sea-level rise of several meters and therefore it potentially affects the lives of many millions of people.
The time it takes before most of the ice in Greenland is lost strongly depends on the level of warming. “The more we exceed the threshold, the faster it melts,” says Alexander Robinson, lead-author of the study now published in Nature Climate Change. In a business-as-usual scenario of greenhouse-gas emissions, in the long run humanity might be aiming at 8 degrees Celsius of global warming. This would result in one fifth of the ice sheet melting within 500 years and a complete loss in 2000 years, according to the study. “This is not what one would call a rapid collapse,” says Robinson. “However, compared to what has happened in our planet’s history, it is fast. And we might already be approaching the critical threshold.”…
And the surprises just keep on coming(click on pic to go to story):
…and unprecedented ‘Ice Quakes'(click on pic to go to story):
3.) The Boreal Forest, which rings the northern latitudes and provides habitat for migratory bird species and other wildlife, could die back within 50 years as trees succumb to summer heat stress, increased diseases and other threats. This is considered an “intermediately sensitive” tipping point with large uncertainty.
The most noteworthy destruction of boreal forests is the extraction of Canadian tar sands:
-Oil sands mining is licensed to use twice the amount of fresh water that the entire city of Calgary uses in a year.
-At least 90% of the fresh water used in the oil sands ends up in ends up in tailing ponds so toxic that propane cannons are used to keep ducks from landing.
-Processing the oil sands uses enough natural gas in a day to heat 3 million homes.
-The toxic tailing ponds are considered one of the largest human-made structures in the world.
-The ponds span 50 square kilometers and can be seen from space.
-Producing a barrel of oil from the oil sands produces three times more greenhouse gas emissions than a barrel of conventional oil.
PDF of report here via ::DeSmogBlog
As if the hellish blight of tar sands operations was not enough of a sacrifice zone for our unsustainable lifestyles, plans are being laid to duplicate the process for America’s own oil sands project in Utah.
An administrative law judge in Salt Lake City has ruled against two environmental organizations that are trying to block a Canadian company’s plan to open the first large-scale oil sands mine in the United States.
Judge Sandra Allen sided with U.S. Oil Sands and Utah’s Division of Water Quality in deciding that the state rightfully granted the Calgary-based company permission to mine and process oils sands without requiring a pollution permit or water monitoring at the PR Spring mining site in eastern Utah. The judge agreed with the Water Quality Division’s opinion that there is so little ground water within 1,500 feet of the surface of the proposed mine that additional safeguards weren’t needed.
The northern boreal forests comprise almost one third of the Earth’s forest systems, covering 1.5 billion hectares. Along with the temperate forest of the mid-latitudes, and tropical forest near the equator, it is one of the three great forest ecosystems of the world, supporting a rich diversity of wildlife, endangered species, and extremely valuable timber…
…There is general consensus that climatic changes will have the greatest impact on boreal forests; their unique adaptation makes them more sensitive to temperature fluctuations than temperate or even tropical forests. Indeed, fossil pollen and macro fossil records demonstrate that North American boreal forests expanded and receded in response to temperature changes over the past 10,000 years. Even a slight increase in mean annual temperature is enough to affect many species’ growth and regeneration…
…The rate of climate change — and not the change itself — is perhaps the biggest threat to the boreal forest. With rapid change, conditions may become unsuitable for trees to complete their life cycle. Seedlings are especially sensitive to short-term drought, saplings to varying levels of sunlight, and mature trees to soil moisture during the growing season. Thus, in a kind of “arrested development,” healthy-looking tree populations may not ever mature to the point of reproduction. Entire remnant stands of forest may no longer sustain themselves, or their resident animal and plant communities. A temperature rise of only 2 degrees C could, for example, eliminate up to half of the animals currently inhabiting boreal mountain ranges from the Rocky Mountains to the Sierra Nevada…
4.) The West Antarctic Ice Sheet could collapse within 300 years, leading to a sea level rise of as much as 15 feet worldwide. This is considered an “intermediately sensitive” tipping point with large uncertainty.
A new study sheds light on the vulnerability of the Antarctic to climate change(clink on the pic to go to story):
5.) The Amazon rainforest could die back significantly within 50 years due to a combination of deforestation and global warming, which could trigger a 30% decrease in rainfall. This is considered an “intermediately sensitive” tipping point with large uncertainty.
The Amazon Rainforest is expected to be reduced by 40% by 2030 at the current rate of deforestation, despite recent reductions. A current scientific paper states that due to deforestation, the Amazon is becoming a net CO2 emitter rather than a sink for the world’s carbon dioxide. When we take into account the uncertainties of climate change-induced droughts, the prospect of losing one of the earth’s major lungs becomes a near certainty:
…One of the scarier possibilities to emerge from this body of work is worth dwelling on a bit, simply because it would be so devastating if it came to pass: the so-called Amazon dieback scenario. Many scientists were deeply skeptical of the idea when it was first published, but events in the last few years have made them less dismissive.
The scenario emerged most clearly in computer analyses in Britain led by Peter M. Cox of the University of Exeter and published in 2000 as a paper in the journal Nature. Running a large-scale computer simulation in which forests interacted with a changing global climate through the course of the 21st century, the Cox group found that forests would continue to take up carbon until about 2050.
But then, their computer predicted, warmer temperatures and water stress would cause a huge dieback of the Amazon forest, which would stop absorbing carbon and start emitting it as a result.
That was a startling possibility for many reasons, not the least being that the Amazon is the richest single ecosystem left on the planet, and functioning as a major carbon sponge is only one of the critical roles it plays. Might the Amazon really die as a direct consequence of human-induced climate change?…
…[That question] took on a new urgency in 2005, however, when a severe drought hit the Amazon region, killing many large trees. In 2010, there was an even larger drought with potentially worse damage — two “once a century” droughts just five years apart. The 2010 drought is still under study; some evidence suggests that the 2005 drought was linked to high Atlantic Ocean temperatures that may in turn be linked to human emissions of carbon dioxide.
The droughts raise a disturbing question: Could the great dieback predicted for midcentury already be starting?
Scientists do not know. They say the effects of the two droughts are likely to be transient, but only if similar events do not recur anytime soon. Oliver L. Phillips, a researcher at the University of Leeds, led a team that documented a huge loss of carbon in the Amazon because of the 2005 drought. “The most likely outcome is that the forest will gain all that carbon back, and then some,” he said in an interview.
But he and other scientists say that if the Amazon starts experiencing such droughts every few years, all bets are off.
“It’s a worrisome moment for the Amazon,” said Daniel C. Nepstad, an American scientist working at the Amazon Environmental Research Institutein Brazil to understand the pressures on the forest. “This is either just a big coincidence that we had these two severe droughts in close sequence, or it is a sign of things to come.”…
Satellite view of deforestation in Rondônia, Brazil, 1975 and 2012
Despite recent efforts by Brazil to curb deforestation, it continues at a ferocious pace outside Brazil’s borders:
Amazon deforestation grows outside Brazil – SFGate
…In Brazil, the enforcement of land-use laws reduced deforestation by 76 percent in eight years, from 10,424 square miles in 2004 – when a swath bigger than Maryland was cleared of jungle – until last year, when the country’s National Institute for Space Research reported that 2,471 square miles had been destroyed.
But more than 40 percent of the Amazon jungle is beyond Brazil’s borders, spread across eight countries in a carpet of green six times the size of California. These countries are poorer and less stable than Brazil, with less capacity to control clear-cutting of trees. Government agencies that regulate land use are spread thin, and some of those countries, including Bolivia, actively promote development in the jungle.
Satellite data and field work by environmental and forestry ministries in the region show that deforestation in the non-Brazilian Amazon rose from an annual average of 1,930 square miles in the 1990s to 2,779 square miles last year.
“There’s more deforestation going on in the Andean Amazon than in the Brazilian Amazon,” said Timothy Killeen, an ecologist and geographer in Bolivia who works with environmental groups and has been studying deforestation in the Amazon for 25 years. “Before, Brazilian deforestation was four times as great as in the Andean Amazon. Now the Andes has more. We’re winning the battle in Brazil but losing the battle in the Amazon.”
Environmentalists say the destruction of the Andean Amazon is particularly worrisome because it affects the lifeblood of the entire Amazon, the rivers flowing down from the Andes.
This post is part one of a three-part series. In the second part I will talk about the other climate change tipping points as described by Professor Tim Lenton.
I imagine a child born today would look at all adults as grotesque monsters. With the world we are leaving them, how could they see us otherwise…