Tuesday, July 26, 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


Wednesday, July 6, 2011

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..."

Saturday, June 11, 2011

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 NiƱa, 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  NameSymbol
  English           Multiple (SI)Name (SI)Symbol (SI)English(SI)
                                   100gramggram
                                    103kilogramKgthousand g 
 100tonne     t 1 tonne                   106megagramMgmillion g 
 103kilotonne    kt 1 thousand tonnes   109gigagramGgbillion g 
 106megatonne    Mt 1 million tonnes       1012teragramTtrillion g 
 109gigatonne    Gt 1 billion tonnes        1015petagramPgquadrillion g
   1012teratonne    Tt 1 trillion tonnes        1018exagramEg
   1015petatonne    Pt 1 quadrillion tonnes  1021zettagramZg
   1018exatonne    Et                               1024yottagramYg


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. 
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.
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 9.4oF (5.2oC) 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 13.3oF (7.4oC), 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 4oC 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 4oC.
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

Saturday, May 28, 2011

Biomass

Traditionally, biomass has been used in four ways:
 1. For industrial purposes (shelter, building materials, furniture, utensils, etc)
 2. Burning (for domestic energy use such as heating, lighting and cooking, and for land clearance) 
 3. Conservation (left on land or added to soil as compost, to enrich soil and biodiversity, avoid erosion, etc.) 
 4. For food (including livestock feed, while using fertilizers and with waste dumped in landfills or sea)


In the light of rising costs of fossil fuel and climate change concerns, other uses are considered, specifically: 
 5. Low-footprint food (reduced meat and reduced use of chemical fertilizers, with waste processed)
 6. Commercial combustion in power plants, furnaces, kilns, ovens and internal combustion engines
 7. Burial 
 8. BECCS (Bio-Energy with Carbon Capture & Storage)
 9. Biochar (Pyrolysis resulting in biochar, syngas and bio-oils)
10. Biochar + BECCS (Biochar + Bio-Energy with Carbon Capture & Storage)

Table 1. Comparison of methods to process biomass (Energy and Carbon)
 Combustion Burial BECCS Biochar Biochar + BECCS
 Energy - year 0  1.0 -0.1 0.8 0.5 0.5
 Carbon - year 0 -0.1  1.0 0.8 0.5 0.9
 Energy - out years 0.4 0.4
 Carbon - out years 0.5 0.5
 Total  0.9  0.9 1.6 1.9 2.3
Above table by Ron Larsen, from this message, shows five methods to process biomass, rated (with 1.0 being the highest score) for their ability to supply energy and for their ability to remove carbon from the atmosphere.  

Above table shows that each way to process biomass waste has advantages and disadvantages:
 6. Combustion may seem attractive for its supply of energy, while having negative impact due to emissions 
 7. Burial can minimize emissions, but it doesn't provide energy, in fact it costs energy
 8. BECCS can score high on immediate energy supply as well as on avoiding carbon emissions
 9. Biochar scores well regarding immediate energy supply and emissions, with additional future benefits
10. Biochar + BECCS has all the benefits of biochar, while also capturing and storing pyrolysis emissions

The table below also incorporates above-mentioned traditional use of biomass, while using a wider footprint, i.e. with scores not only reflecting the ability of the method to remove carbon from the atmosphere, but also looking at emissions other than carbon.

Table 2. Comparison of ten uses of biomass (Energy and Footprint)
Energy - year 0Footprint - year 0Energy - out yearsFootprint - out yearsTotal
Industrial -0.1 0.1 0.0
Burning 1.0-1.0
   0.0
Conservation  -0.2
  -0.2
Food  -0.3 -0.3
Low-footprint food  
 0.0
Combustion 1.0-0.1
 0.9
Burial-0.1 1.0  0.9
BECCS 0.8  0.8 
 1.6
Biochar 0.5  0.50.4   0.5 1.9
Biochar +BECCS 0.5  0.9 0.4   0.5 2.3

Biochar gets its positive "out years" scores for increasing vegetation growth over time, as it improves soil's water and nutrients retention, while also reducing the need for chemical fertilizers. 

These qualities of biochar are also helpful in efforts to bring vegetation into the desert by means of desalinated water, as proposed by a number of scientists. A study by Leonard Ornstein, a cell biologist at the Mount Sinai School of Medicine, and climate modelers David Rind and Igor Aleinov of NASA's Goddard Institute for Space Studies, all based in New York City, concludes that it's worth while to do so.
They envision building desalination plants to pump seawater from oceans to inland desert areas using pumps, pipes, canals and aqueducts. The idea is that this would result in vegetation, with the tree cover also bringing more rain -- about 700 to 1200 millimeters per year -- and clouds, which would also help reflect sunlight back into space.
This would not only make these deserts more livable and productive, it would also cool areas, in some cases by up to 8°C .
Importantly, vegetation in the deserts could draw some 8 billion tons of carbon a year from the atmosphere -- nearly as much as people now emit by burning fossil fuels and forests. As forests matured, they could continue taking up this much carbon for decades.
The researchers estimate that building, running, and maintaining reverse-osmosis plants for desalination and the irrigation equipment will cost some $2 trillion per year.

Monday, April 18, 2011

How would you allocate US$10 million per year to most reduce climate risk?

Imagine that you had a budget of $10 million per year and that you should maximize the amount of climate risk reduction obtainable with that $10 million, what would you allocate it to and why?

Given the scary situation in the Arctic, I would apportion parts of the $10 million to methods that promise immediate results:
  1. R&D and testing of SRM methods such as surface brightening and marine cloud brightening.
  2. R&D and testing of ways to ignite or break down methane from the sky, i.e. from airplanes or satellites. Laser beams spring to mind. Another technology that could be looked at further is to focus short, amplified pulses of light on water vapor, hydrogen peroxide or ozone, in efforts to produce more hydroxyl (OH) which could in turn oxidize as much methane as possible.
  3. Building on the outcome of 2., equipping small aircraft with such technology, as well as autopilot software, GPS, LiPo batteries and with solar thin film mounted both on top of and underneath the wings.
example aircraft
At first, as a test, two such small aircraft could navigate on auto-pilot to the north of Canada and Alaska at the start of Spring on the Northern Hemisphere.

In subsequent years, numerous such planes could follow, also going to other parts of the Arctic. At the end of Summer, the planes could return home for a check-up and possible upgrade of the technology, to be launched again the next year.

There are many self-financed clubs where members build and fly remote controlled aircraft, as discussed in comments underneath this post.

Even a small financial incentive could help such clubs make a lot progress and give them a goal, while the publicity would also make people more aware of the problems we face in the Arctic.

Such aircraft could navigate the Arctic, guided by satellite detection of methane concentrations (image left) and by equipment carried onboard, such as small versions of methane analyzers.

Measuring from different vantage points can pinpoint the most suitable location to cross-aim multiple laser beams at, to minimize the energy needed to heat up methane to its point of auto-ignition (image below).



Methane can be ignited where it is present in concentrations of between 5% and 15%. In concentrations of around 9%, methane could be ignited with as little as 0.3 mj of energy (see image, adapted from Zabetakis).

At well over 500 degrees Celsius, methane's minimum auto-ignition temperature is rather high. Other volatile hydrocarbons in the vicinity may ignite at lower temperatures (with less energy), in turn igniting the methane.



Sam Carana

For further background on the above, also see:
http://geo-engineering.blogspot.com/2011/04/runaway-global-warming.html
and
http://groups.google.com/group/geoengineering/browse_thread/thread/5eaf812314dced8c