Arctic News

Monday, October 22, 2012

Lethally Hot Temperatures During the Early Triassic Greenhouse

Paleogeographic reconstruction of the Early Triassic world (Smithian substage) around 250 million years ago, with
a ‘dead zone’ in the tropics. Presence of marine reptiles (ichthyosaurs), terrestrial tetrapods and fish was almost exclusively in higher latitudes (>30 °N and >40 °S) with rare exceptions. Credit: Yadong Sun, University of Leeds

The end-Permian mass extinction, which occurred around 250 million years ago, wiped out nearly all the world's species. Typically, a mass extinction is followed by a 'dead zone' during which new species are not seen for tens of thousands of years. In this case, the dead zone, during the Early Triassic period which followed, lasted for five million years.

A study jointly led by the University of Leeds and China University of Geosciences (Wuhan), in collaboration with the University of Erlangen-Nurnburg (Germany), shows the cause of this lengthy devastation was a temperature rise to lethal levels in the tropics: around 50-60°C (122-140°F) on land, and 40°C (104°F) at the sea-surface.

Lead author Yadong Sun, who is based in Leeds while completing a joint PhD in geology, says: “Global warming has long been linked to the end-Permian mass extinction, but this study is the first to show extreme temperatures kept life from re-starting in Equatorial latitudes for millions of years.”

The dead zone would have been a strange world – very wet in the tropics but with almost nothing growing. No forests grew, only shrubs and ferns. No fish or marine reptiles were to be found in the tropics, only shellfish, and virtually no land animals existed because their high metabolic rate made it impossible to deal with the extreme temperatures. Only the polar regions provided a refuge from the baking heat.

Before the end-Permian mass extinction the Earth had teemed with plants and animals including primitive reptiles and amphibians, and a wide variety of sea creatures including coral and sea lillies.

This broken world scenario was caused by a breakdown in global carbon cycling. In normal circumstances, plants help regulate temperature by absorbing carbon dioxide and burying it as dead plant matter. Without plants, levels of carbon dioxide can rise unchecked, which causes temperatures to increase.

Professor Paul Wignall from the School of Earth and Environment at the University of Leeds, one of the study's co-authors, said: “Nobody has ever dared say that past climates attained these levels of heat. Hopefully future global warming won't get anywhere near temperatures of 250 million years ago, but if it does we have shown that it may take millions of years to recover.”

References

- Lethally Hot Temperatures During the Early Triassic Greenhouse
http://www.sciencemag.org/content/338/6105/366.abstract

- Tropical collapse caused by lethal heat
http://www.eurekalert.org/pub_releases/2012-10/uol-tcc101712.php

Related

- How extreme will it get?
http://arctic-news.blogspot.com/2012/07/how-extreme-will-it-get.html

- The potential impact of large abrupt release of methane in the Arctic
http://arcticmethane.blogspot.com/2012/05/potential-impact-of-large-abrupt.html

- Methane in the Arctic
http://arctic-news.blogspot.com/2012/05/video-and-poster-methane-in-arctic.html

Thursday, October 18, 2012

Is death by lead worse than death by climate? No.

Paul Beckwith,
B.Eng, M.Sc. (Physics),
Ph.D. student (Climatology)
and Part-time Professor,
University of Ottawa

by Paul Beckwith

Is death by lead worse than death by climate? That depends on your perspective. If you are the person dying then death by climate most likely means death by starvation. Or by dehydration. Or by painful vomiting and diarrhea from drinking contaminated water. It seems to me that this slow, painful death by climate would be much worse than catching a lead projectile from afar most likely with little or no warning.

If you are a journalist then penning death by lead stories allows you to write things that appeal to the visceral; namely to write about human conflict between “good” and “evil” and showing vivid images. People seem to innately enjoy reading about the competition of war or battle or insurgency and be able to cheer for a victor. To arms suppliers, it allows them to increase their profit margins. In addition, it allows politicians to have a rallying patriotic cry about the responsibility of their respective country to exercise some muscle with the pretense that they actually care about the well-being people being killed in another far off country. Or say that it is necessary to restore or create some democracy in such a country while ignoring the loss of democracy in their own country. Clearly hypocrisy. Almost inevitably armed intervention leads to a magnification of death and destruction.

How can western politicians, backed by an incredibly supportive and unquestioning main stream media and catering to the interests of large corporations make so much rah-rah about 20,000 people that have experienced death by lead in an internal conflict in one specific year in some other country while completely ignoring the deaths, every single year of 400,000 people?

That is the number of people, mostly children that are dying each year from climate change and carbon economies according to the DARA study that was released September 27th. Somehow this has been ignored up to now. However what politicians cannot ignore so easily is the claim in the same report that the global economy is losing 1.6% of GDP every year due to climate change. Today. Not in a decade or a century but today. This cannot be ignored so easily. In fact the Saturday Globe and Mail discussed the vanishing Arctic sea ice causing global extreme weather events causing global food supply disruption in a lengthy article on the front page of the Sept. 27th Business section. An image of the sea ice minimum of September 16th was even on the next page. Never before in the history of the Globe have I seen such a thing! Why was the article there? Not because of concern for sea ice or worry of extreme weather but because of the 1.6% GDP loss occurring today. Expected to rise to 3.5% of GDP loss 2030. Things are different now. Our world is changing rapidly, in real-time, before our very eyes. Just watch a video of the ice this summer. We have never experienced abrupt climate change before.

For decades, many climatologists have been warning that the energy balance of the earth is out of wack. Now, to the tune of the equivalent of 0.6 Watts per square meter over the entire surface of the planet. Isn’t this small, a Christmas tree bulb is a Watt or two? No. James Hansen calculated that this imbalance is equivalent to the energy of 300,000 Hiroshima sized bombs popping off every single second on every day of the year, year in and year out. Half of this energy is warming the atmosphere and half is warming the ocean. It is not small at all. Sounds like insanity to me. But I am biased. I live and breathe climatology and meteorology. Thus I know the dangers that climate change can bring much more deeply than others and I want to bring others up to speed. Quickly.

Methane hydrates: a volatile time bomb in the Arctic

By Carlos Duarte, University of Western Australia
and Antonio Delgado Huertas, Spanish Scientific Research Council CSIC

Methane locked under the Arctic ice could take climate change to a whole new level. Antonio Delgado Huertas

The risk with climate change is not with the direct effect of humans on the greenhouse capacity of Earth’s atmosphere. The major risk is that the relatively modest human perturbation will unleash much greater forces. The likelihood of this risk is intimately tied to the developments over the next decade in the Arctic.

Accelerating ice loss and warming of the Arctic is disturbing evidence that dangerous climate change is already with us. As I have argued earlier, now that we have realised this our efforts should be directed at managing the situation in the Arctic and avoiding the spread of dangerous climate change elsewhere.

The Arctic is a core component of the earth system. Six of the 14 climate change tipping points of the earth system are located in the Arctic region.

Whereas the term tipping point was initially introduced to the climate change debate in a metaphoric manner, it has since been formalised and introduced in the context of systems exhibiting rapid, climate-driven change, such as the Arctic. Tipping points have been defined in the context of earth system science as the critical point in forcing at which the future state of the system is qualitatively altered.

Tipping elements are defined, accordingly, as the structural components of the system directly responsible for triggering abrupt changes once a tipping point is passed. This is because they can be switched into a qualitatively different state by small perturbations.

Of the many tipping elements in the Arctic, that with potentially greatest consequences if perturbed is the vast methane deposit. Methane is a greenhouse gas. A molecule of methane has 20 times the greenhouse effect of a CO₂ molecule, and the release of methane has been linked to climatic transitions along the history of planet Earth.

The Arctic contains vast reserves of methane stored as methane hydrate, a gel-like substance formed by methane molecules trapped in frozen water. The methane hydrate deposits are estimated at between 1,000 and 10,000 Gigatons (10⁹ tons) of CO₂-equivalents as methane, much of which is present in the shallow sediments of the extensive Arctic shelves. This amount of greenhouse gas is several times the total CO₂ release since the industrial revolution.

Even moderate (a few degrees C) warming of the overlying waters may change the state of methane from hydrates to methane gas, which would be released to the atmosphere. If this release is gradual, methane will add a greenhouse effect to the atmosphere. This will only be temporary, as it will be oxidised to CO₂, with a decline in the greenhouse effect of 20-fold per unit carbon.

However, if the state shift is abrupt it may lead to a massive release of methane to the atmosphere, which could cause a climatic jump several-fold greater than the accumulated effect of anthropogenic activity.

Data collected on a recent cruise confirm methane is being emitted. Antonio Delgado Huertas

Recent assessments have found bubbling of methane on the Siberian shelf. Models suggest that global warming of 3°C could release between 35 and 94 Gt C of methane, which could add up to an additional 0.5°C of global warming. Moreover, frozen soils and sediments contain large amounts of methane hydrates that can be released to the atmosphere. Indeed, rapid thawing of the Arctic permaforst has been reported to lead to the release of large amounts of methane.

In our most recent cruise this summer (June 2012) along the Fram Strait and Svalbard Islands we found concentrations of methane in the atmosphere of about 1.65 ppm. However our equilibrium experiments (air atmospheric with Arctic surface water) reached values that were generally between 2.5 ppm and 10 ppm, with maximum values up to 35 ppm. These results confirm that this area of the planet is emitting large amounts of methane into the atmosphere.

Understanding and forecasting the response of Arctic methane hydrate deposits to rapid warming and thawing in the Arctic is of the utmost importance.

Provided the magnitude of these risks, and those associated with other tipping elements in the Arctic, our collective response to climate change appears to be a careless walk on the razor edge.

Carlos Duarte receives funding from the Spanish Ministry of Economy and Competitiveness and the EU R&D 7th Framework Program to conduct research in the Arctic. He is affiliated, through a joint appointment, with the Spanish National Research Council (CSIC).

Antonio Delgado Huertas receives funding from Ministry of Economy and Competitiveness (Spain).

This article was originally published at The Conversation.
Read the original article.

Editor's note: For a discussion of the potency of methane compared to carbon dioxide, see the post Methane in the Arctic.

Tuesday, October 16, 2012

Albedo change in the Arctic threatens to cause runaway global warming

Mark Flanner et al. calculated in 2011 that snow and ice on the Northern Hemisphere had a combined cooling effect of 3.3 Watts per square meter (of which 2 W/m² relates to the snow cover on land and 1.3 W/m² to the sea ice).

This cooling effect is diminishing rapidly, as temperatures rise and snow and ice cover declines. Snow and ice on the Northern Hemisphere had already declined substantially over the years and was reflecting 0.45 watts less energy per square meter in 2011 than it did in 1979 (Flanner, 2011).

As discussed in Albedo change in the Arctic, Professor Peter Wadhams calculates that the loss of the Arctic sea ice cooling effect alone can be compared to the net global warming caused by people's emissions (1.66 W/m², IPCC, 2007b).

From: sites.google.com/site/arctischepinguin/home/piomas

The exponential trends added by Wipneus to PIOMAS Arctic sea ice volume data show that the Arctic Ocean looks set to be ice-free from 2015 onwards for the period from August through to October, while July and November look set to follow from 2017, respectively 2018 onwards with June following closely thereafter. In other words, we could soon face an Arctic Ocean that is ice-free for half the year.

Snow cover on land takes up an even larger area than sea ice. The chart below illustrates the decline of snow cover on land in the Northern Hemisphere (without Greenland) for the month June.

What trends could fit these data? On the image below, I've added trendlines and I encourage others to come up with better ones.

Clearly, a lot of snow and ice looks set to disappear over the next few years. Note that what happens in winter doesn't matter as much, as little sunlight reaches the Arctic in winter. What matters most is how much sunlight is reflected when insolation in the Arctic is high. Insolation during the months June and July is higher in the Arctic than anywhere else on Earth, as shown on the image below, by Pidwirny (2006).

While Greenland remains extensively covered with snow and ice, the reflectivity of its cover shows rapid decline, as illustrated by the image below. The July data since 2000, from the meltfactor blog with projection in red added by Sam Carana, suggest a exponential fall in reflectivity that looks set to go into freefall next year.

From: Greenland is melting at incredible rate

Albedo: wikipedia.org/wiki/Albedo

A drop of as little as 1% in Earth’s albedo corresponds with a warming roughly equal to the effect of doubling the amount of carbon dioxide in the atmosphere, which would cause Earth to retain an additional 3.4 watts of energy for every square meter of surface area (NASA, 2005; Flanner et al., 2011).

Combined, the snow line retreat, loss of sea ice and decline of Greenland's reflectivity constitute a huge loss of summer cooling in the Arctic.

As a result, summer temperatures in the Arctic look set to rise rapidly over the next few years, threatening to unleash massive amounts of methane from sediments below shallow waters of the Arctic Ocean, spiraling Earth into runaway global warming.

If you are also concerned about this development, please share the image below at Facebook, with a link to this post.