Every few days, it seems, another factor is discovered to further accelerate Climate Destabilization. Today we learned that increasing CO2 makes ice crack faster.
... CO2 molecules may be having a more direct impact on the ice that covers our planet. Researchers from the Massachusetts Institute for Technology have shown that the material strength and fracture toughness of ice are decreased significantly under increasing concentrations of CO2 molecules, making ice caps and glaciers more vulnerable to cracking and splitting into pieces,...
Ice caps and glaciers cover seven per cent of Earth -- more than Europe and North America combined -- and are responsible for reflecting 80-90 per cent of the Sun's light rays that enter our atmosphere and maintain Earth's temperature. They are also a natural carbon sink, capturing a large amount of CO2.
"If ice caps and glaciers were to continue to crack and break into pieces, their surface area that is exposed to air would be significantly increased, which could lead to accelerated melting and much reduced coverage area on the Earth.
... CO2molecules first adhere to the crack boundary of ice by forming a bond with the hydrogen atoms and then migrate through the ice in a flipping motion along the crack boundary towards the crack tip.
The CO2 molecules accumulate at the crack tip and constantly attack the water molecules by trying to bond to them. This leaves broken bonds behind and increases the brittleness of the ice on a macroscopic scale. [emphasis mine]
As the world's coral reefs bleach out, many are being colonized by algae, which can inhibit recolonization by new coral polyps. Now we learn that more algae also cause higher microbe numbers, and increase the probability they're pathogens. Carbon cycling slows, impacting fish numbers.
In this newly abundant population of microbes, evolutionary selection pressures favor microbes that endanger corals, either by depleting oxygen from the environment or through disease. As the corals die off, the algae have even more space to take over,... creating a runaway feedback loop that leads to further coral death and microbes taking over the ecosystem.
... microbialization associated with increasing algae cover in coral reefs can decimate the reef ecosystem through microbial takeover.
... 'microbialization' destroys links in coral reefs' delicate food chain.
... they found that reef sites with higher algal cover also had more microbes. Using metagenomic sequencing techniques, they found that in algae-dominated reefs, the microbial community is more likely to harbor harmful pathogens. [order changed, emphasis mine]
Another positive feedback: glacier melt increases pink snow, which lowers albedo to increase melt.
... so-called pink snow, which Arctic explorers have observed for centuries, is the result of a red algae...
The presence of red algae, the study found, lowers the snow’s albedo, or its ability to reflect light instead of absorbing it as heat...
... it’s an example of how human-caused climate change functions on a positive feedback loop ...
“The algae need liquid water in order to bloom,” she said. “Therefore the melting of snow and ice surfaces controls the abundance of the algae. The more melting, the more algae. With temperatures rising globally, the snow algae phenomenon will likely also increase leading to an even higher bio-albedo effect.”
The latest new positive climate change feedback is that melting in East Antarctica's Wilkes Basin could facilitate widespread coastal melt.
This research concludes that local melting from the Wilkes Basin in East Antarctica “could potentially destabilise the wider Antarctic Ice Sheet” as meltwater rapidly stratifies surface waters so, whilst the surface ocean cools, the Southern Ocean warms by more than 1°C at depth. “The temperature changes propagate westwards around the coast of the Antarctic continent with increasing depth, representing a positive feedback mechanism that has the potential to amplify melting around the continent… Thus, destabilisation of large sectors of the EAIS could arise from warming and melting in just one area.” As well: “Our results suggest that melting of one sector of the EAIS could result in accelerated warming across other sectors, including the Weddell Sea sector of the West Antarctic Ice Sheet” (emphasis added).
Quote lifted from Shawn Redmond's comment at Robert Scribbler.
Original article (very long)
Greenland's two hottest summers each produced a solitary wave of mass loss in Rink Glacier, another new positive feedback that no one had imaged.
A new NASA study finds that during Greenland's hottest summers on record, 2010 and 2012, the ice in Rink Glacier on the island's west coast didn't just melt faster than usual, it slid through the glacier's interior in a gigantic wave, like a warmed freezer pop sliding out of its plastic casing. The wave persisted for four months, with ice from upstream continuing to move down to replace the missing mass for at least four more months.
This long pulse of mass loss, called a solitary wave, is a new discovery that may increase the potential for sustained ice loss in Greenland as the climate continues to warm, with implications for the future rate of sea level rise.
Rink is one of Greenland's major outlets to the ocean, draining about 11 billion tons (gigatons) of ice per year in the early 2000s... In the intensely hot summer of 2012, however, it lost an additional 6.7 gigatons of mass in the form of a solitary wave. [emphasis mine]
James Hansen's 15 minute video gives a clear explanation of how the Atlantic Meriodonal Overturning Circulation (AMOC) could shut down this century, causing irreparable harm. The IPCC didn't forsee this because their models ignored ice melt. The effect of ice melt fresh water lenses is the positive feedback overlooked.
He's amazingly articulate. The comparison to how *45 communicates hit me in the face.
Deforestation causes twice as much rise in global temperature as we'd thought, when nitrous oxide and methane co-emissions are counted.
When that area's loss as a carbon sink for the long term is added to the immediate carbon costs of deforestation, that also doubles the carbon impact.
… nitrous oxide and methane—are released after natural lands have been converted to agricultural and other human usage.
As a result, while only 20 percent of the rise in carbon dioxide caused by human activity originates from land use and land-cover change, that warming proportion from land use (compared with other human activities) increases to 40 percent once co-emissions like nitrous oxide and methane are factored in.
… a previous paper she published in January, … showed that the carbon released by a deforested area is actually doubled over time because that area’s future potential to function as a natural sink … has been eliminated.
“Normally people only think about what’s happening right now when they think about the carbon budget,” Mahowald says. “But if you think about what’s going to happen over the lifetime of that land, long into the future, you should multiply that land conversion by two to understand the net effect of it.”
As the atmosphere heats, it expands, causing clouds to form higher and to move toward the poles. This causes clouds to re-emit less of the heat they'd absorbed.
A warmer Earth elevates clouds because the troposphere, the lowest layer of our atmosphere where weather occurs, can extend higher with a hotter surface. Warming also moves clouds poleward because circulation patterns in the tropics are expanding, pushing storms north and south.
But there’s a bigger issue at play here: These perturbed clouds may cause further warming, triggering a vicious cycle of increasingly rising global temperatures. That critical detail was often glossed over as news of the cloud changes spread last month.
Heat absorbed and then re-emitted by low clouds that are close to the ground is similar to the heat emitted by the surface because the temperature of the ground and the cloud are similar.
But the higher the cloud is in the sky, the colder it is. So when these high clouds absorb Earth’s heat, they re-emit it at a much lower temperature,...causing even more warming of the climate system. [emphasis mine]
New research indicates that methane emissions from freshwater ecosystem will double within 50 years due to changes in vegetation driven by climate change. The impact of vegetation type on lake sediment emission is a newly discovered feedback mechanism. Cattail (bullrush) debris creates far more methane than tree debris, and climate change favors cattails over trees.
The flourishing reed beds created by changing climates could threaten to double the already significant methane production of the world's northern lakes.
... the findings suggest the discovery of yet another "feedback loop" in which environmental disruption and climate change trigger the release of ever more greenhouse gas that further warms the planet, ...
" Freshwater ecosystems already contribute as much as 16% of the Earth's natural methane emissions, compared to just 1% from all the world's oceans," said study senior author Dr Andrew Tanentzap..."
... Tanentzap's group found that the levels of methane produced in lakes varies enormously depending on the type of plants contributing their organic matter to the lake sediment.
... bulrush sediment produced over 400 times the amount of methane as the coniferous sediment, and almost 2,800 times the methane than that of the deciduous.
Unlike the cattail debris, the chemical makeup of the organic matter from trees appears to trap large quantities of carbon within the lake sediment --... [emphasis mine]
As oceans warm, a microlayer of scum called biological surfactants suppresses wind driven carbon dioxide exchange at the surface more.
An invisible layer of scum on the sea surface can reduce carbon dioxide exchange between the atmosphere and the oceans by up to 50%, scientists have discovered.
... the findings ... have major implications for predicting our future climate.
The world’s oceans absorb around a quarter of all man-made carbon dioxide emissions, making them the largest long-term sink of carbon on Earth.
“The warmer the ocean surface gets, the more surfactants we can expect, and an even greater reduction in gas exchange." [emphasis mine]
As climate change worsens, air conditioning needs will soar. But that increased demand will have its own feedback effect on mortality through increases of particulates and ozone depletion. Researchers ...
... predict future mortality associated with increased emissions from power plants caused by demand for air conditioning. Their modelling study considers different climate increases with or without adaptation. They predict increases of 4.8% and 8.7% respectively for particulate- and ozone-associated deaths above climate change impacts alone. [emphasis mine]
! How does that compare to deaths from other causes? No matter the numbers, we would like every person to have a good, long, healthy life, not cut short!
Not to mention the positive climate-change feedback from emissions from generating the electricity for all that air conditioning!
How can it be made acceptable and imperative for families to conceive fewer children? (Reminded me of Bill McKibben's book Maybe One: A Case for Smaller Families, whose title sums up his thoughts about how many children a couple should consider bringing into the world. Of course, that's no reason for eager parents not to adopt kids who are already around!)
Flash-thawing of permafrost beneath thermokarst lakes (formed on land-based permafrost when a thawed area sinks and collects water) is a significant new feedback.
… thermokarst lakes …develop when warming soil melts ground ice, causing the surface to collapse and form pools of water. Those pools accelerate permafrost thaw beneath the expanding lakes, providing food for microbes that produce the greenhouse gases carbon dioxide and methane.
… the "abrupt thaw" beneath such lakes is likely to release large amounts of permafrost carbon into the atmosphere this century. The lake activity could potentially double the release from terrestrial landscapes by the 2050s.
… the release of greenhouse gases beneath thermokarst lakes is relatively rapid, with deep thawing taking place over the course of decades. Permafrost in terrestrial environments generally experiences shallow seasonal thawing over longer time spans.
"Instead of centimeters of thaw, which is common for terrestrial environments, we've seen 15 meters of thaw beneath newly formed lakes ... within the past 60 years."
Emissions from thermokarst lakes aren't currently factored into global climate models…
… not including them in global climate models overlooks their feedback effect, which occurs when the release of greenhouse gases from permafrost increases warming. That feedback is significant because methane is about 30 times more potent than carbon dioxide as a heat-trapping gas.
Existing models currently attribute about 20 percent of the permafrost carbon feedback this century to methane, with the rest due to carbon dioxide from terrestrial soils. By including thermokarst lakes, methane becomes the dominant driver, responsible for 70 to 80 percent of permafrost carbon-caused warming this century. [emphasis mine]