Creating extra ice in winter for extra cooling in summer

Ulan Bator, the capital of Mongolia, is considering creating extra ice in winter.

A Mongolian engineering firm ECOS & EMI aims to drill bore holes into ice formed on the Tuul river in winter. The water will be discharged across the surface, where it will freeze. This process - effectively adding layers of ice rinks - will be repeated at regular intervals throughout the winter.

The idea is that this can help cool and water the city as the ice melts during the summer.

Source: Mongolia bids to keep city cool with 'ice shield' experiment - The Guardian, November 15, 2011.

Combining Policy and Technology

Technologies to remove carbon dioxide from the atmosphere

The Virgin Earth Challenge is a prize of $25m for whoever can demonstrate to the judges' satisfaction a commercially viable design which results in the removal of anthropogenic, atmospheric greenhouse gases so as to contribute materially to the stability of Earth’s climate.

Among the 11 shortlisted organizations are:

• biochar (Biochar Solutions, Black Carbon and Full Circle Biochar)
• carbon capture, particularly from ambient air (Carbon Engineering, Kilimanjaro Energy and Climeworks)
• enhanced weathering (Smart Stones)

Above three technologies (biochar, carbon air capture and enhanced weathering) have great potential to help out with carbon dioxide removal (CDR) from the atmosphere. To combat global warming, further technologies should be considered, such as in Solar Radiation Management (SRM) and Arctic Methane Management (AMM).

How effective each technology is in one area is an important consideration; importantly, each such technologies can also have effects in further areas.

Further areas

Global warming is only one out of multiple areas where action is required; an example of another area is the hole in the ozone layer over Antarctica; effective action has already been taken in this area, but the growing hole in the ozone layer over the Arctic shows that further action is necessary.

A safe operating space for humanity is a landmark 2009 study by Rockström et al. It identifies nine essential areas where sustainability is stressed to the limits, in three cases beyond its limits.

Areas and applicable technologies

The table below shows these nine areas on the left, while technologies that could be helpful in the respective area feature on the right.

As said, each of technologies may be able to help out in multiple areas. As an example, by reducing carbon dioxide levels in the atmosphere, biochar and carbon air capture can also indirectly reduce carbon dioxide in oceans and thus help out with ocean acidification. Enhanced weathering could additionally reduce carbon dioxide in the oceans directly, thus presenting itself even more prominently as a proposal to achieve sustainability in this area.

Similarly, algae bags located in the mouth of a river could help out in multiple areas. They could produce biofuel and thus help reduce aviation emissions, while in the process catching fertilizer runoff, thus reducing emissions of nitrous oxide (the largest ozone-depleting substance emitted through human activities in a 2009 NOAA study) and also reducing depletion of oxygen in oceans.

1. Climate Change		CDR: biochar, carbon air capture, enhanced weathering, algae bags, EVs, renewable energy, clean cooking & heating, LEDs, etc. SRM: surface and cloud brightening, release of aerosols AMM: methane capture, oxygen release, river diversion, enhanced methane decomposition
2. Ocean acidification		enhanced weathering
3. Stratospheric ozone depletion		oxygen release
4. Nitrogen & Phosphorus Cycles		algae bags, biochar, enhanced weathering
5. Global freshwater use		desalination, biochar, enhanced weathering
6. Change in land use		desalination, biochar, enhanced weathering
7. Biodiversity loss		desalination, biochar, enhanced weathering
8. Atmospheric aerosol loading		biochar, EVs, renewable energy, clean cooking & heating, LEDs, etc.
9. Chemical pollution		recycling, waste management (separation)

Implementing the most effective policies

Policy support for such technologies is imperative. Just like some technologies can help out in several areas, some policies can cover multiple areas. As an example, a policy facilitating a shift to cleaner energy can both reduce greenhouse gases and aerosols such as soot and sulfur. Sulfur reflects sunlight back into space, so reducing sulfur emissions results in more global warming, but conversely global warming can be reduced by releasing sulfur over water at higher latitudes.

How many different policies would be needed to support such technologies? What are the best policy instruments to use?

Traditionally, government-funded subsidies and standards have been used to contain pollution, sometimes complemented with levies and refundable deposits; this can also work for chemical pollution. Standards have also proven to be effective in reducing the impact of CFCs on the ozone layer, while - as said - policies could at the same time also be effective in other areas, in this case reducing the impact of CFCs as greenhouse gases.

However, standards don't raise funding for support of such technologies, while taxpayer-funded subsidies make everyone pay for the pollution caused by some. Hybrid methods such as cap-and-trade and offsets are prone to corruption and fraud, which compromises their effectiveness. Local feebates are most effective in facilitating the necessary shifts in many areas.

Two sets of feebates

To facilitate the necessary shift away from fuel toward clean energy, local feebates are most effective. Fees on cargo and flights could fund carbon air capture, while fees on fuel could fund rebates on electricity produced in clean and safe ways. Fees could also be imposed on the engines, ovens, kilns, furnaces and stoves where fuel is burned, to fund rebates on clean alternatives, such as EV batteries and motors, solar cookers and electric appliances. Such feebates are pictured as yellow lines in the top half of the image below.

Support for biochar and olivine sand could be implemented through a second set of feebates, as pictured in the bottom half of the image below. Revenues from these feebates could also be used to support further technologies, as described in the paragraph below.

Further technologies should be considered for their effectiveness in specific areas, including:

• release of oxygen to help combat methane in the Arctic and to help combat loss of stratospheric ozone
• use of plastic sheets to capture methane
• use of radio waves to enhance methane decomposition
• diversion of water from rivers to avoid warm water flowing into the Arctic Ocean
• release of aerosols over water at higher latitudes
• surface & cloud brightening to reflect more sunlight back into space

Professor Schuiling proposes olivine rock grinding

Dutch Professor Olaf Schuiling has been working on rock grinding for many years. Remember the Virgin Earth Challenge, launched early 2007 with the promise to award $35 million to the best method to remove greenhouse gases? Schuiling said: Let's grind more rocks! Last thing Schuiling heard was that he was among the final ten contenders.

Schuiling's method is simple. Crush olivine rock to small pieces and it will bind with carbon dioxide. This process - called weathering - happens in nature but takes a long time. Crushing and grinding olivine rock will speed up the process and is therefore often called enhanced weathering. It works best in wet tropical countries, but can be done everywhere around the world.

Schuiling proposes to cover beaches, levees and railway tracks with the material, and proposes olivine to be added to building materials like pavement and concrete. It can also be added to soil and water. Adding olivine can fertilize the soil and improve its ability to retain water, and can work well in combination with biochar and other ways to increase organic carbon in the soil. When added to the sea, it can reduce acidification, and stimulate growth of diatoms and other forms of biomass in the sea.

This is a win-win solution, Schuiling says, as it helps grow more food, while combating global warming. To add another win, it can also produce drinking water that is healthier than rain water. Schuiling recommends cities to build olivine hills, to remove carbon dioxide from the air while filtering water.

There's is a video with more background, in Dutch with English subtitles. Also have a look at this poster.

Comments

What works best is implementation of feebates that put in place combinations of local financial incentives and disincentives, as illustrated by the image on the right.

Energy feebates, working in a parallel yet complimentary way, can clean up energy supply within a decade, while feebates as pictured above can continue to bring carbon dioxide levels in the atmosphere back to 280 ppm, as well as bring down carbon dioxide levels in the oceans.

Rock grinding should be part of a comprehensive policy that also includes replacing fuel with renewable energy and support for biochar. The latter is also discussed in the posts Biochar and The Biochar Economy.

As the above diagrams try to show, biochar and olivine sand can be combined in soil supplements, to help bring carbon dioxide levels in the atmosphere back to 280ppm. Rebates could be financed from fees on nitrogen fertilizers, livestock products and Portland cement.

Enhanced weathering is possible with other types of rock, but more easily done with olivine. The paper Olivine against climate change and ocean acidification includes the map below with the global distribution of dunite massifs. By removing their lateritic overburden, the underlying dunites (rocks that consists of > 90% olivine) can be mined. 

As the image on the right shows, there's no need for long distance transport. One dot often represents several dunites and olivine is available in abundance at many places across the globe.

The benefits are great and this looks like one of the most economic ways to bring down carbon dioxide levels. 

The energy can come from wind energy, which is clean, price-competitive and available in abundance in many places. Rock grinding, the transport and distribution can be largely automated, and take place predominantly at off-peak hours, while wind energy can be supplied very economically at off-peak hours.

Olivine sand can also be combined well with biochar, as soil supplement. Have a look at the post the Biochar Economy.

Further reading:
Feebates
Biomass
Carbon Air Capture and Algae Bags
Enhanced weathering
Oxygenating the Arctic
Ozone hole recovery
Enhanced methane decomposition
Desalination
Vortex towers could vegetate deserts
Carbon-negative building
LEDs: When will we see the light?
Thermal expansion of the Earth's crust necessitates geo-engineering
Towards a Sustainable Economy
The way back to 280 ppm

Thermal Expansion of the Earth's Crust Necessitates Geo-engineering

THERMAL EXPANSION of the Earth's crust due to global warming risks disturbing Arctic methane hydrates, and the process has already started, necessitating geo-engineering, argues Sam Carana, editor of the Geo-engineering Blog.

In a search for the smoking gun, locations of Arctic temperature anomalies were used to pinpoint methane emission points, which were subsequently matched with seismological data.  

Extrapolation of the data points at Total Extinction Zones during which all organic life on Earth risks going extinct, due to accelerating release of methane from Arctic hydrates destabilized by Gakkel Ridge earthquake activity.

This danger necessitates geo-engineering, argues Sam Carana, insisting that temperatures of the water deep down in the Arctic Ocean need to be brought down rapidly, while carbon dioxide levels need to be brought back to 280ppm in the course of this century, as part of a comprehensive plan of action that will lead us Towards a Sustainable Economy. 

Editor's note: An extended version of this post is at the Arctic-news blog. 

The Biochar Economy

The Biochar Economy offers a sustainable alternative to economic systems that fail to sufficiently take into account care for the environment and concerns for global warming.

Biochar is one of the products of pyrolysis, an oxygen-starved method of heating up biomass to (also) produce renewable energy.

The Australian Government plans to award carbon credits for the application of biochar to soil, for biochar's ability to abate greenhouse gases. As part of the Carbon Farming Initiative $AU2 million will be provided for a Biochar Capacity Building Program. This in addition to $AU1.4 million that is already being invested in the National Biochar Initiative as part of the Climate Change Research Program.

Carbon credits constitute just one way to support biochar. Ultimately, carbon credits are typically paid from profits on fossil fuel, which are scheduled to decrease over time. To develop more lasting support for biochar, alternatively policies should be considered.

The idea behind the "Biochar Economy" is to try to embed biochar production into as many processes as possible, as pictured on above image, from open source ecology.

In carbon-negative 'Biochar Economies', biochar is proposed to also act as a kind of local 'gold standard' for local currency supply. Biochar-based currency could strengthen local economies and shield them not only from the volatility of global currency fluctuations, but also from the danger of global warming causing the entire global financial system to collapse, as discussed back in 2007.

Biochar-based local currencies go well together with three types of local feebates: 

• Energy fees, imposed on polluting fuel and the equipment and appliances used to burn the fuel, to fund rebates on local clean energy programs.
• Fees on polluting cement, livestock products and nitrogen fertilizers, made payable in local currency, funding rebates on locally-produced biochar and olivine added to local soils.
• Local rates that incorporate feebates, i.e. higher fees the lower the soil's carbon content, with rebates for soils with the highest carbon content.

Since pyrolysis of surplus biomass can produce renewable energy, it can benefit from local energy feebates as pictured below. 

In addition, soil supplements that include biochar can benefit from feebates as pictured below. 

These policies will avoid emissions and effectively take greenhouse gases from the atmosphere. 

These policies will also create local employment and investment opportunities without having to borrow money elsewhere, and will increase local standards of living and health, as well as increase the quality and value of the land. 

All this can be achieved though mechanisms that work in parallel and are often complementary, e.g. pyrolysis of forest waste can stimulate forest growth, avoid termite infections and reduce the risk of wildfires; furthermore, when pyrolysis provides power that replaces the practice of burning firewood and fossil fuel to power lighting and cooking, this will also reduce the risk of lung infections.

To increase demand for the local currency, rebates on local clean energy programs and soil supplements could be paid out in local currency. Furthermore, a community can call for local rates and fees on products such as fuel, polluting cement, livestock products and nitrogen fertilizers to be paid in local currency.

Much crop is now used to grow feed for livestock ― less livestock could free up land that could be used to produce food & wood, and the associated organic waste. Furthermore, such feebates can avoid soil erosion and deforestation, and instead result in more vegetation, thus further increasing the amount of biomass available for pyrolysis.

Below are some further ways pyrolysis can be integrated in the local economy:

• Pyrolysis of biomass is an excellent way of handling organic waste, while producing useful products such as biochar, biooils and gases such as hydrogen. Biooil and hydrogen can be used to power aviation and shipping.  
• Bioasphalt^® is a type of asphalt made from bio-oil. According to its manufacturer, it can save energy and money, since it can be mixed and paved at lower temperatures than conventional asphalt. 
• Apart from burial of biochar to enhance soil fertility, biochar can also be used to manufacture a range of products, including vehicle bodies made of carbon fiber and capacitors. 
  
  A team at Stevens Institute of Technology has designed, fabricated, and tested a prototype supercapacitor electrode made from biochar. The team demonstrated biochar's feasibility as an alternative to activated carbon for supercapacitor electrodes. Currently, supercapacitors use activated carbon. The team estimates that biochar costs almost half as much as activated carbon, apart from being more sustainable. 
  
  Supercapacitors can be used to power electric buses. Ultracapacitor buses by Sinautecus have been operational in the Greater Shanghai area since August 2006, as mentioned under this post on electric bus systems.

More reading at:

Feebates

Biochar

Biomass

Vortex towers could vegetate deserts

Carbon-negative building

Towards a Sustainable Economy
Comprehensive Plan of Action

Carbon-negative technologies

The image below, adapted from Negative Emissions Technologies report by Duncan McLaren (version 2, 2011), pictures a number of carbon dioxide removal (CDR) methods. 

For further discussion of biomass use, see the post Biomass; for further discussion of policy issues, see The way back to 280 ppm and Towards a Sustainable Economy. 

Runaway Warming

Thermal expansion

As mentioned in Ten dangers of Global Warming, one of the biggest dangers is that, without dramatic action, the atmosphere will reach certain tipping points beyond which sudden dramatic and catastrophic changes will take place. 

As Earth warms up, tectonic plates will expand and some areas will come under increasing pressure, especially along fault lines where tectonic plates collide. As described in this comment and this post, this could lead to earthquakes. Thermal expansion of land and water could put more stress on areas prone to seismic activity, triggering earthquakes that can make the greenhouse effect much worse. The danger is that such seismic activity will cause slope failure in regions with methane hydrates that are already unstable and vulnerable due to global warming.   

Ice and glaciers melting away

Links between climate change and geological and geomorphological phenomena were the theme of this 2009 conference. Several speakers addressed the danger that, as ice and glaciers in the mountains melt away, a substantial weight is disappearing, changing pressures that act on the Earth's crust and contribute to seismic activity. This link was confirmed in several scientific studies, such as this one dating back to 2003. 

Hydrates disturbed by drilling and fracking

There is also an indirect risk. Melting of Arctic sea ice may open up sea routes to hydrates. Drilling and fracking in these hydrates could trigger earthquakes, especially if they're already under extra stress, resulting in the release of huge amounts of methane. This is particularly worrying in the Arctic, where waters can be very shallow, leaving less opportunity for methane to be broken down in the water.

Deep Ocean Warming

The ocean conveyor belt transports water--and heat--around the globe, as shown on the image left, from a NSF press release describing recent research by scientists at NCAR and the Bureau of Meteorology in Australia, which found that deep oceans can warm by 18% to 19% more during a period corresponding with a La Niña event. 

Global warming is likely to cause thermal expansion of the oceanic crust, putting stress on areas where tectonic plates meet. Such a warming peak deep in the ocean could put enough extra stress on these areas to trigger earthquakes that in turn disturb hydrates, resulting in huge amounts of methane to be released. The NOAA image below shows how the Mid-Atlantic Ridge continues into the Arctic Ocean. 

Gakkel Ridge

One place to watch is Gakkel Ridge, the boundary between the North American Plate and the Eurasian Plate. Earthquake activity along Gakkel Ridge has been rising since 1970. Earthquakes in the Gakkel Ridge area could send shockwaves into the shallows of the Arctic Ocean. 

Between 1999 and 2000 alone, there was an anomalously large number of earthquakes along the Arctic Gakkel Ridge (more than 250). In addition, two very unusual and extremely violent submarine pyroclastic eruptions occured in the central Gakkel Ridge region. 

Of the earthquakes measured on the Arctic Gakkel Ridge between March 19th 1980 and the 31st December 2010, most (94%) were strong enough to cause widespread collapse of the methane hydrates and release of methane plumes into the water column and atmosphere. [source: globalwarmingmlight.blogspot.com]

Runaway Warming

In conclusion, global warming can accelerate in a number of ways, including thermal expansion of tectonic plates, causing landslides and shocks from earthquakes, while extra stress can be added due to deep ocean warming peaks and a change in weight as ice retreats on land. This could be ameliorated by drilling and fracking activities.

The danger is that this will put increasing stress on hydrates that can contain huge amounts of methane. If such hydrates are disturbed, huge plumes of methane can be released, causing supersaturation of waters with methane. As a result, further methane releases will enter the atmosphere without being oxidized in the water. The risk is that such methane releases lead to runaway global warming. 

This risk is unacceptable, making it imperative to reduce emissions and bring atmospheric carbon dioxide down, which is best achieved by means of feebates and requires a number of geoengineering techniques, as discussed in Sustainable Economy. In Geoengineering the climate (Royal Society, 2009) various geoengineering methods are compared. These methods may differ in timescale, cost-effectiveness and wider impact (see e.g. this posts on Biomass), but the urgency to act on global warming is such that we may well need all of them to avoid runaway global warming.  

[adapted from NOAA image - click to enlarge]

Geoengineering field testing

A team of British academics will in October 2011 start conducting field-tests, pumping water into the air from a balloon at a height of 1km. Ultimately, they aim to test pumping sulphates into the stratosphere from a balloon at 20 km height.

The balloon could also be used to test "cloud whitening", i.e. pumping up fine sea salt crystals and spraying them into the air to increase the number of droplets and the reflectivity in clouds.

Source: Giant pipe and balloon to pump water into the sky in climate experiment
Also see: Space Hose
Press Release: The SPICE project: a geoengineering feasibility study (September 14, 2011)


Editor's note: The test, part of the UK-based Stratospheric Particle Injection for Climate Engineering (SPICE) project that receives £1.6m support from UK research councils, has meanwhile been put on hold, following the councils' advisory panel's recommendation to delay the project.


Source: Climate fix technical test put on hold (BBC News, September 30, 2011)
Also see: Political backlash to geoengineering begins (New Scientist, October 3, 2011)

The way back to 280 ppm

Concentration of carbon dioxide in the atmosphere reached 394.97ppm at Mauna Loa in May — 41% above the 280ppm it had been for thousands of years before the Industrial Revolution started.

Given the dangers of global warming, carbon dioxide needs to get back to 280ppm. Emission cuts alone will not be able to accomplish this, so what more can be done?

Emissions cut 80% by 2020,
Sam Carana, March 18, 2008

Large drops in carbon dioxide have taken place in history, and are attributed to weathering, i.e. rocks breaking down and carbonates being deposited on ocean floors. However, it takes nature many, many years to do this. To make this happen at accelerated rates, carbon dioxide removal methods can be deployed that are typically referred to as mineral carbonation and accelerated weathering.

At first glance, one may suggest implementation of policies such as cap-and-trade or cap and capture to make those who put carbon into the atmosphere pay for its removal. More effective, though, is a combination of two types of feebates, working separately, yet complimentary, to get emissions cut 80% by 2020 and carbon dioxide on the way back to 280ppm.

Many carbon dioxide removal methods are energy-intensive. As long as the energy used is expensive and polluting, not much can be achieved. A rapid shift to clean energy is necessary, which is best facilitated through energy feebates.

As the number of solar and wind facilities grows, large amounts of clean electricity will become available at off-peak hours, when there's little demand for electricity. This will make such electricity cheap, bringing down the cost of methods such as enhanced weathering, which can take place at off-peak hours. Such energy will also make carbon dioxide removal more effective, since the energy is clean to start with.

Energy feebates as pictured above can best clean up energy, while other feebates can best raise revenue for carbon dioxide removal.

Energy feebates can phase themselves out, completing the necessary shift to clean energy within a decade. Carbon dioxide removal will need to continue for much longer, so funding will need to be raised from other sources, such as sales of livestock products, nitrogen fertilizers and Portland cement.

A range of methods to remove carbon dioxide would be eligible for funding under such feebates. To be eligible for rebates, methods merely need to be safe and remove carbon dioxide. Methods could remove carbon dioxide from the atmosphere and/or from the oceans.

Rebates favor methods that also have commercial viability. In case of accelerated weathering, this will favor production of building materials, road pavement, etc. Such methods could include water desalination and pumping of water into deserts, in efforts to achieve more vegetation growth. Selling a forest where once was a desert could similarly attract rebates.

Some methods will be immediately viable, such as afforestation and biochar burial. It may take some time for methods such as enhanced weathering to become economically viable, but when they do, they can take over where afforestation has exhausted its potential to get carbon dioxide back to 280ppm.

For further discussion, also see Towards a Sustainable Economy

Geoengineering Politics: Research Moving Ahead in the UK

Geoengineering Politics: Research Moving Ahead in the UK: 

"The Engineering and Physical Sciences Research Council (EPSRC), a British government funding agency, has released initial funding for two g..."

Earth at Boiling Point

Silence before the Storm

Here's an analogy to describe the precarious situation we're in. When heat is added to water at boiling point (100°C or 212°F), vapor will appear at the surface, while bubbles of gas are formed throughout the water, but the water's temperature will not rise. All added energy is absorbed in the water, transforming it from a liquid to a gas. This is illustrated by the image below, adapted from ilpi.com.

Similarly, Earth is now at boiling point, i.e. the situation has reached a point where - at first glance - it may appear as if there's little or no change. Rises in global temperature, as illustrated by the chart below, based on data by the National Oceanic and Atmospheric Administration (NOAA) with standard polynomial trendline added, may seem only mild.

Many will hardly notice global warming, due to the variability of short-term weather conditions locally.

Furthermore, we’ve had a strong La Niña, which pushes temperatures down, while we’ve been in a solar minimum, as some call it: “the deepest solar minimum in nearly a century”. 

As the image on the right shows, differences in irradiation can amount to a difference in warming of up to 0.25 W/m². 

So, impressions that the impact of global warming was only mild can be deceptive.  

The NOAA image below shows a steady increase in carbon dioxide over the years. At the same time, the image also shows little or no increase at all for some other emissions over the past decade, particularly for methane (CH₄). 

Again, such impressions can be deceptive, as this may make people assume that methane will continue to show little or no increase in future. Instead, the boiling-point analogy is more appropriate to describe the situation regarding methane. Similar to bubbles that start forming in water at boiling point, methane bubbles are forming in the Arctic.

Arctic Sea Ice losses

At the European Geosciences Union annual meeting, Professor Wieslaw Maslowski, who works at Naval Postgraduate School in Monterey, California, unveiled the results of advanced computer modeling that produces a "best guess" date of 2016 for Arctic waters to be ice-free in summers. The study follows his team's 2007 projection that the dramatic loss of ice extent in 2007 set the stage for Arctic waters to be ice-free in summers within just 5-6 years.

Also illustrative is the image below, from Arctic Sea Ice Blog.

Feedback Effects in the Arctic

Disappearing sea ice will cause albedo changes in the Arctic, amplifying the warming taking place there. The color of the sea is darker than the ice that previously covered it.

Another albedo change is taking place on land. The forested landscape in Siberia may over the course of a year absorb between 2 and 7% more solar radiation, reinforcing local warming trends. 

Temperature rises are further amplified by additional feedback effects such as releases of nitrous oxide and methane. 

So, while it may appear that there has been little or no rise in methane for some time, the prospect of future methane emissions looks very scary. 

Due to amplification of global warming in the Arctic, temperatures can now be 10°C or 18°F higher than average temperatures were 1951-1980 (NASA image left).. 

Most methane emissions occur at the northern hemisphere's high latitudes (Wikipedia image below).

At first glance, it may seem as if there's nothing to worry about. Methane releases have historically been stronger at high latitudes of the northern hemisphere, as  illustrated by the NOAA image left (with Mauna Loa data highlighted in red). 

However, levels of methane in the Arctic can be expected to rise dramatically, as discussed below.

The image below shows the current extent of Arctic permafrost, as part of a study by Edward Schuur that estimates that there is some 1672 petagrams (GT or billion metric tons, see table below) of carbon in the Arctic permafrost - roughly equivalent to a third of all carbon in the world's soils and about twice the amount of carbon contained in the atmosphere.

The figures mentioned in above paragraph were also used in the report by the Copenhagen Diagnosis, where authors further pointed at the amplifying feedback effect in high northern latitudes of microbial transformation of nitrogen trapped in soils to nitrous oxide.

Apart from Arctic releases of carbon dioxide, there is the potential for releases of nitrous oxide and methane. Much methane is also present in Arctic waters and in sediments underneath the water. Due to methane's high initial global warming potential (GWP), large abrupt releases of methane could lead to runaway global warming, as further discussed below.

The terrifying prospect is that, within a time-span of only a few years, huge methane releases in the Arctic will spread around the globe, covering Earth in a heat-trapping blanket and moving our biosphere beyond its biological boiling point.

Units of measurement

Multiple	Name	Symbol		English           Multiple (SI)	Name (SI)	Symbol (SI)	English(SI)
				100	gram	g	gram
				103	kilogram	Kg	thousand g
100	tonne	t		1 tonne                   106	megagram	Mg	million g
103	kilotonne	kt		1 thousand tonnes   109	gigagram	Gg	billion g
106	megatonne	Mt		1 million tonnes       1012	teragram	T	trillion g
109	gigatonne	Gt		1 billion tonnes        1015	petagram	Pg	quadrillion g
1012	teratonne	Tt		1 trillion tonnes        1018	exagram	Eg
1015	petatonne	Pt		1 quadrillion tonnes  1021	zettagram	Zg
1018	exatonne	Et		1024	yottagram	Yg

Methane's Global Warming Potential (GWP)

The image below, from the Intergovernmental Panel on Climate Change (IPCC), shows that methane levels have already been rising dramatically since the industrial revolution.

Over the years, the IPCC has upgraded methane's global warming potential (GWP). In 1995, the IPCC used a figure of 56 for methane's GWP over 20 years, i.e. methane being 56 times more powerful than carbon dioxide by weight when comparing their impact over a period of 20 years. In 2001, the IPCC upgraded methane's GWP to 62 over 20 years, and in 2007 the IPCC upgraded methane's GWP to 72 over 20 years.

Large releases could make that much of the methane could remain in the atmosphere longer, without getting oxidized. Initially, much of the methane is oxidized in the sea by oxygen (when released from underwater sediments) and in the atmosphere by hydroxyl. Over time, however, accumulation of methane could cause oxygen and hydroxyl depletion, resulting in ever more methane entering the atmosphere and remaining there for a longer period. 

A two-part study by Berkeley Lab and Los Alamos National Laboratory shows that, as global temperature increases and oceans warm, methane releases from clathrates would over time cause depletion of oxygen, nutrients, and trace metals needed by methane-eating microbes, resulting in ever more methane escaping into the air unchanged, to further accelerate climate change.

A 2009 study by Drew Shindell et al. shows that chemical interactions between emissions cause more global warming than previously estimated by the IPCC. The study shows that increases in global methane emissions have already caused a 26% decrease in hydroxyl (OH). Because of this, methane now persists longer in the atmosphere, before getting transformed into the less potent carbon dioxide.

A Centre for Atmospheric Science study suggests that sea ice loss may amplify permafrost warming, with an ice-free Arctic featuring a decrease in hydroxyl of up to 60% and an increase of tropospheric ozone (another greenhouse gas) of up to 60% over the Arctic.

Extension of methane's lifetime further amplifies its greenhouse effect, especially for releases that are two or three times as large as current releases. 

The graph on the right, based on data by Isaksen et al. (2011), shows how methane's lifetime extends as more methane is released.

The image below, from a study by Dessus et al., shows how the impact of methane decreases over the years. In the first five years after its release, methane will have an impact more than 100 times as potent as a greenhouse gas compared to carbon dioxide.

The GWP for methane typically includes indirect effects of tropospheric ozone production and stratospheric water vapor production. The study by Isaksen et al. shows (image below) that a scenario of 7 times current methane levels (image below,medium light colors) would correspond with a radiative forcing of 3.6 W/m^-2.

Such an increase in methane would thus add more than double the entire current net anthropogenic warming (for comparison, see Wikipedia image below).

For many years, the amount of methane has remained stable at about 5 Gt annually (NOAA image below). A scenario of 7x this amount would lift the amount of methane in the atmosphere to about 35 Gt.

A scenario of seven times the amount of methane we're used to having in the atmosphere would give the methane a lifetime of more than 18 years, so there's no relief from this burden in sight, while this would triple the entire net effect of all emissions added by people since the industrial revolution. 

Arctic concentration makes the situation even worse

What makes things even worse is that all this methane would initially be concentrated in the Arctic, whereas GWP for greenhouse gases is typically calculated under the assumption that the respective greenhouse gas is spread out globally.

All this methane will initially be concentrated locally, causing huge Arctic amplification of the greenhouse effect in summer, when the sun doesn't set. 

The methane will heat up the sea, causing further lack of of oxygen in the water, while algae start to bloom, making this worse, and lack of hydroxyl in the air.

In a vicious circle that will further accelerate the permafrost melt, this will cause further releases from permafrost and clathrates.

Uninhabitable Planet

Back in 2009, I pointed at projections of a MIT study showing that, without rapid and dramatic action on global warming, global median surface temperature will rise by 9.4^oF (5.2^oC) by 2100.

The wheel on the right depicts the MIT's estimate of the range of probability of potential global temperature rise by 2100 if no policy is enacted on curbing greenhouse gas emissions.

The wheel on the left assumes that aggressive policy is enacted, and projects a lower rise.

The projections show rises ranging up to 13.3^oF (7.4^oC), based on probabilities revealed by 400 simulations.

But even the worst-case scenario in the above MIT-study may actually understate the problem and the speed with which this may eventuate, since the model does not fully incorporate positive feedbacks such as large-scale melting of permafrost in arctic regions and subsequent release of large quantities of methane.

Several teams of scientists warn that we can expect a rise of 4^oC within decades. A rapid rise in temperature is likely to make the areas where most people now live uninhabitable, leaving humans, mammals and plants little on no time to migrate to cooler areas. The image below (edited from New Scientist) shows that the currently inhabited part of the planet would become largely uninhabitable with a global temperature rise of 4^oC.

Above image gives some suggestions as to action that can be taken, such as reforestation and construction of clean energy facilities. The image also shows that habitable areas may be restricted to the edges of the world where there's little sunshine. A specific area can become uninhabitable due to sea level rises or heat stress. Humans simply cannot survive prolonged exposure to temperatures exceeding 95°F (35°C), explains Steven Sherwood. An area can also become uninhabitable due to recurring wildfires, floods, droughts, storms and further extreme weather events that cause erosion, desertification, crop losses and shortages of fresh water. 

Back in 2007, I pointed at the danger of tipping points beyond which human beings face the risk of total extinction, particularly if many species of animals and plants that humans depend on will disappear. The boiling point analogy shows that there may be a window of time to act, like a silence before the storm. This realization should prompt us to speed up implementation of the necessary policies while we can. In fact, abrupt large releases of methane may close that window rather quickly, as described in Runaway Global Warming and The potential for methane releases in the Arctic to cause runaway global warming.