Cross Posted on Reporting on a Revolution

In the November 25 issue of Current Science, researchers from the Indian Space Research Organization release a map and some important estimates of the extent of land degradation and desertification affecting mainly dry, semi-arid and dry- sub humid areas of India.

Land Degradation: Land Use and Processes

Source: Desertification/land degradation status mapping of India

About 69% of the total land area of the country – about 228 million hectares – falls in one of these three climatic categories. The numbers from this mapping project is cause for concern. They indicate that land degradation has affected just under half the extent – 105 million hectares of these dryland regions, roughly 32% of the land area of India.

The main processes of degradation are water erosion, wind erosion and vegetal degradation through deforestation and overgrazing. The paper gives the extents affected by various degradation processes grouped state-wise.

I wish they had included estimates of degradation by land use. For example how much of agricultural land in each state is being degraded, how much forest and so on. These have been no doubt calculated. They show up as classes on the map, but the paper does not present the results by type of land use affected.

If predictions about changing rainfall patterns over India because of climate change turn out to be accurate they will accentuate many of these degradation processes. Rainfall is predicted to fall in shorter more intense bursts over many regions of India. This would mean more powerful surface runoff and greater soil erosion.

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Cross posted at Reporting on a Revolution.

The more familiar method of carbon dioxide sequestration involves capturing and pumping the gas into underground reservoirs where geological traps that have sealed natural gas for millions of years will serve to lock captured CO2 for eons as well.

Nature has published a paper by Jürg M. Matter and Peter B. Kelemen that proposes another method of CO2 sequestration, locking CO2 as carbonate minerals by reaction with a host rock.

Anthropogenic greenhouse-gas emissions continue to increase rapidly despite efforts aimed at curbing the release of such gases. One potentially long-term solution for offsetting these emissions is the capture and storage of carbon dioxide. In principle, fluid or gaseous carbon dioxide can be injected into the Earth’s crust and locked up as carbonate minerals through chemical reactions with calcium and magnesium ions supplied by silicate minerals. This process can lead to near-permanent and secure sequestration, but its feasibility depends on the ease and vigour of the reactions. Laboratory studies as well as natural analogues indicate that the rate of carbonate mineral formation is much higher in host rocks that are rich in magnesium- and calcium-bearing minerals. Such rocks include, for example, basalts and magnesium-rich mantle rocks that have been emplaced on the continents. Carbonate mineral precipitation could quickly clog up existing voids, presenting a challenge to this approach. However, field and laboratory observations suggest that the stress induced by rapid precipitation may lead to fracturing and subsequent increase in pore space. Future work should rigorously test the feasibility of this approach by addressing reaction kinetics, the evolution of permeability and field-scale injection methods.

The advantage here is that the gas is converted into a solid phase and so exists in a more stable form. The principle may be sound but I’m going to think out aloud on bridging the very long distance between scientific possibility and its practical realization in the field for a country like India.

First come the political and economic issues with a scheme of this nature. Those hurdles are immense. India’s stated position is of no mandatory limits on emissions, so there is no political urgency in examining CO2 sequestration projects like this one. And this method is going to be expensive as well. Transporting CO2 from emission points to suitable storage sites and then drilling and pumping gas in hard rock ain’t going to come cheap. It might work if the price of emitting CO2 is very high. But under the current scenario in India with no limits or penalties on emissions there will be no economic incentives for polluters to even explore a scheme like this.

Besides, there are other urgent practical matters that need to be carefully thought out before rock masses can be given out for CO2 storage.

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Cross Posted From Reporting On A Revolution

From Brave Blue Words I found out that Thursday Oct 15  was Blog Action Day for Climate Change. Bloggers all over the world are writing about various aspects of climate change.

Being a geologist I want to point to a study that reconstructs atmospheric CO2 levels as far back as the Miocene  – a 20 million year history. Atmospheric CO2 levels have been reconstructed with some confidence for the last 800,000 years or so using gas bubbles trapped in the Antarctic ice sheets. Before that the data was thin.

Aradhna Tripati and colleagues have used the boron to calcium ratio in foraminifera shells to calculate ancient CO2 levels. As atmospheric CO2 increases some of it diffuses into the ocean increasing the dissolved CO2 content of sea-water. That in turn reduces the amount of boron that is incorporated in a growing calcium carbonate shell of the foraminifer individual. The variation in the boron to calcium ratio over time as recorded in foraminfera fossils of different ages should tell us something about transitions in CO2 levels.

The scientists first validated their calculations using the 800 K record of CO2 trapped in ice. They compared their results with those obtained by the direct measurement of CO2 trapped in gas bubbles. It was a good match. The scientists calculate that the uncertainty in their results is about 14 parts per million.

Their results show that there is a close coupling between CO2 levels, sea-level and temperature over the last 20 million years.  In the middle Miocene (~ 20 ma) CO2 levels were about 400 ppm – comparable to modern levels – and that sea-levels at that time were 30 -40 meters higher than today (geologists estimate this using distribution of ancient shorelines), with temperatures about 3-6 deg C higher (using geochemical proxies like the oxygen isotope composition of shells which depend partly on temperature of the water from which they precipitate). Decreases in CO2 levels in the later part of Miocene and Pliocene were synchronous with major episodes of cooling and glacial expansion.

Its important to establish that historical connection to answer doubts expressed on what exact impact would increasing levels of CO2 have on climate and sea-level. Many climate change doubters are not happy with computer simulations and models of CO2 increase and climate change. This study shows that CO2 has been a strong driver and amplifier of climate change in the deep geological past. History is also a guide and often a reliable one.

Go here for the press release.A minor quibble. The press release calls the shells used by the scientists as belonging to single celled marine algae. Foraminifera are not algae. They are protists.

I don’t know what to make of this calculation which I picked up in a New Scientist story. A few weeks ago there was a study using NASA’s Grace satellite measurements that showed an increase in groundwater extraction from North Indian aquifers.

A second study on these satellite measurements asserts that the groundwater loss amounts to about 54 cubic km per year over a time period of 2002 and 2008. A lot of this extracted groundwater ends up in the sea and could be contributing to raising sea-levels by 0.16 millimeters every year, about 5% of the total sea level rise. That is about the same as contributed by runoff from melting Alaskan glaciers the authors conclude.

I don’t have access to the full paper so I don’t know the details of the calculation but here is what the scientists have to take into account:

Part of the groundwater extracted will be taken up by plants and remain there over the life of the plant and make its way into the food chain.
Part of it will be lost through the plants through evapo-transpiration.
Part of the water will remain in soil adhering to clay and sand particles.
Part of it will make its way back to the aquifer.
Part of it will make its way through the soil to local streams and eventually to the sea.
Part of it will be lost by direct evaporation. That evaporated water (and the water lost by evapo-transpiration) will fall as rain and part of it will infiltrate as groundwater and part of it will be surficial runoff into streams and eventually into the sea.

Just giving you  something to think about what happens to extracted groundwater.

This entry has been cross-posted on Reporting on a Revolution

A friend returned from Australia with stories of water rationing in Melbourne and Adelaide. Can’t water lawns and wash cars. That would invite fines from the city. Coincidentally, national geographic magazine has a feature on Australia’s big dry, a prolonged drought that has decimated farming communities in the Murray Darling basin and forced farmers to sell century old farms and move to cities in search of work.

As always I want to steer the conversation to what is happening in India. A recent regional finer grained climate model from researchers at Purdue University confirms what global climate models have been telling us for some time. That monsoon patterns will change both in the timing of the advent of rains and in the amount of precipitation. The map below shows the across-country expected changes in both these parameters.

Source: Purdue

The basic take away lessons from these studies are that: 1) the country will get hotter 2) rainfall pattern will be more unpredictable 3) rains will be concentrated in shorter more intense bursts 4) periods of drought will last longer 5) overall, regions which experience less rainfall can expect even less rainfall, those that experience a lot ofrain can expect little change or an increase in rain.

I turn again to the National Water Mission, one of the eight focus areas in the National Action Plan for Climate Change (15 mb) It does recognize that water availability and rainfall will vary region by region and proposes a host of measures in its draft report that includes enhancement and better management of groundwater resources as well as surface water resources.

That is fine talk but will the resource allocation and effort match the current pattern of water use? Himanshu Thakkar in a detailed critique of the National Action Plan For Climate Change is pessimistic about any fundamental changes taking place in the way the government thinks about water resources. Yet, today over two thirds of arable lands in India are irrigated by groundwater and over 85% of rural water supply and about 50% of urban and industrial water supply comes from groundwater sources. Historically though it is surface water that has received more attention and funding. Our government planners have always been obsessed with mega infra-structure water projects.

Despite hundreds of kilometers of canals, surface water irrigation helps less than 15% of Indian farmlands. The majority rely on direct rain and groundwater supported by about 20 million irrigation wells. It is the small landholders and marginal farmers who benefit most from groundwater. From 1970 to 1995 marginal farms increased their groundwater irrigated areas by 400 percent as compared with just 1 percent increase for large farms, which seem to rely more on canal irrigation.

Looking at the above numbers, at how the water resources pie is divvied up by users, it is groundwater that should be the priority of the National Water Mission. Its not just the lessons from the past regarding the inadequacy of big dams /canals that should guide a shift in focus, but also the realization that climate change will render these systems even more ineffective in the future. Shorter more intense bursts of rain would mean more vigorous surface flow and soil erosion. This would mean increased rates of siltation of canals and dams and a rapid decrease in storage capacity. And a hotter India would mean increased evaporative losses from larger surface reservoirs. (more…)

This entry has been cross posted at Reporting on a Revolution

The volcanic rock basalt underlies the city of Pune and much of the state of Maharashtra. Its rock mass is made up of an interlocking fabric of crystals and it doesn’t have interconnected pore spaces through which water could be transmitted. The permeability of the rock mass is negligible. But basalts can be prolific aquifers. The reason is the various kinds of fractures and joints that serve to store and transmit water.

I came across a construction site near my house the other day and saw that they had dug a pretty deep hole for a foundation. I could see a thick rock profile consisting of two basalt flows. The upper flow was an amygdaloidal vesicular basalt. The lower one was a compact basalt. These are field terms used to categorize flow units with different physical characteristics. At the junction of the two flows was a fractured zone. The fractures were horizontal giving the basalt a sheeted appearance. And water was flowing out of these fractures at a fair pace. Take a look.

Groundwater flow in Basalt

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At Cryology and Co. David Bressan has a post on world wide groundwater resources maps produced by the “World-wide Hydrological Mapping and Assessment Programme” (WHYMAP). Following the link he provided I found a groundwater map of India on that site. The map below is actually from the web mapping application and attempts to give a very broad overview of the groundwater resources in the subcontinent.

The Himalayas are categorized as having local and shallow aquifers, the Indus-Gangetic plains belong to one homogeneous groundwater basin and the southern peninsular region is a complex hydrogeological province. These are somewhat misleading categories in that they are not mutually exclusive. For example local and shallow aquifers are found all over India. And the Himalayas have plenty of regions of complex hydrogeological structures. But combined with recharge potential the map gives on a broad scale the likely patterns of aquifer yield across the country.  (more…)

This entry has been cross posted at Reporting on a Revolution.

Following on the heels of my previous post in which I attempted to put up arguments in favor of human induced global warming, a stark and scary reminder of what I am up against. A couple of example of climate change illiteracy I picked up from the blogosphere.

This one is from Climate Progress and an interview with Barb Davis White a republican who is running for the 5Th Congressional District in Minnesota.

WHITE: My name is Barb Davis White and I’m running for the 5Th Congressional District against Keith Ellison for the United States House of Representatives, which is called Congress.

ROMM: Where are you on global warming?

WHITE: Well, global warming really has not been proven. There are 30,000 scientists, including Al Gore’s professor, from Princeton, who says that we are now in a cooling stage. And ev-every — also every other climate that has been warmed had better grapes.

ROMM: So you don’t believe in global warming and you don’t think that people caused it.

WHITE: No, I think global warming is a scam. I think it’s a scam to put taxes — more taxes on us, and it’s called carbon taxes. Our environment has never been so clean, and if we want to push global warming, let’s push it on China, where the smog is so thick that you almost need a helmet to breathe. Let’s push it on Africa and see how they adapt to it, because they’re not going to.

And from Pharyngula who got it from Diatomaceous Earth. A letter sent to the local paper in Fargo, North Dakota. Is Fargo really this eerie?!!

When God sent the rain on this Earth for 40 days and nights, all this water had to go someplace so the Earth would be dry again.

Remember, God is the Creator and controls the universe.

God tilted the Earth from its original position and caused all the excess water to rush to the poles, and there he instantly froze the water into the ice formations that exist today. Time is ticking down on God’s time clock.

With all the nuclear bombs that are made and stored for the fast-emerging last battle, this Earth would burn up when these nuclear bombs are set off.

We are not creating global warming – God is tipping the Earth back to its original position on its axis and thus getting all this ice to get ready to move and extinguish the nuclear destructive fires man will create.

Is this being taught in church or at home.? Where do people learn this? Unbelievable! I have come across the first type of illiteracy i.e. the Barb Davis White type in India, but so far not the second. We can find humor in this but it is a rather depressing example of how a religious fundamentalist education can warp your world view. Have you experienced such extreme views in India?

This entry has been cross posted at Reporting on a Revolution

I learned about climate change in geology classes but that was about changes over geological time, about the Pleistocene ice ages and the Eocene -Paleocene Thermal maxima and the Mesozoic warm period and so on. All these had natural causes but I am persuaded by the collective scientific evidence that humans are causing the earth to warm up and will contribute increasingly to global warming over the next few decades. But if someone asks me a very specific question, let’s say “Can you tell me if there have been errors in the measurement of CO2 recovered from air bubbles trapped in ice”, I won’t be able to answer that.

A few days ago a friend emailed me just such an article which accuses scientists of mishandling, misrepresenting and even deceit in measurements and the presentation of climate data. The article is written by a Polish radiologist and well know climate change skeptic Zbigniew Jaworowski. I read through the article realized that a layperson who is not aware of the data favoring human induced climate change might get persuaded that human induced global warming is a fraud. How should I go about making a convincing case that the article misrepresents climate science?

Can I leave aside the specific questions about ice-core CO2 levels, maybe give references that point to original work and then still make broad arguments that show that Jaworowski himself has made very unreasonable assumptions and omitted important facts and that the scientific data is trustworthy. I am going to try doing that. This is a bit like the evolution-creationism debate. I can’t answer very specific biological questions like maybe how a particular protein evolved but over the years I have gathered broad arguments in favor of evolution. I have persuaded some of my friends using these broad level explanations of evolution and I am hoping I can use the same kind of arguments to explain climate change.

Right. So here is what I came up with. Feel free to add your own insights and suggestions on how to improve such arguments. (more…)

This entry was originally made on Reporting on a Revolution on April 16, 2008

From my Geology News Feed a link to a pretty cool application for assessing the impact of sea level rise on coastal areas. The application written by Alex Tingle of Firetree.net uses NASA elevation data and the Google Maps API to create dynamic maps of flooding. I played around a little with Mumbai. It’s tempting to run a disaster scenario. Just choose a sea-level rise of 10-15 meters and watch the city go under water. But the results are not very surprising and not too realistic either. This massive a rise in sea level is at the extreme end of the climate change and sea level rise scenarios possible if the Greenland and West Antarctic ice sheet completely melts. May happen but unlikely for the next couple of centuries.

I wanted to find out whether the elevation data underlying the application was fine enough to depict subtle variations in topography and the effect of a small change in sea-level. I used just a 1 meter rise in sea-level. The resulting map impressed. The flooded areas were restricted to the low-lying mudflats and mangroves along the Panvel, Thane, Mahim, Gorai and Vasai Creeks. The rest of the city was unaffected, which is to be expected since the land surface of Mumbai is hilly in places or has been raised by several meters during land reclamation projects. Climate scientists give scenario based range of values for sea-level rise this century and a sea-level rise of 1 meter by the end of the century is a distinct possibility. This would mean large areas of Mumbai and surrounds will be at risk. Image below shows Mumbai and its suburbs and exurbs. Pink areas are the built up concrete jungle, lighter green is land vegetation, blue is water and dark green-brown areas are tidal mudflats and mangroves.

Mumbai City and Environs

A 1 meter sea-level rise will affect these mudflats the most. Yet at places I have marked with arrows near the Panvel and Thane Creeks, pink is intruding upon the dark-green, which means construction is eating up those low-lying areas. All these new constructions are raised a few meters above the original surface and that may protect them against a future sea-level rise. But there are other factors at play and these were demonstrated with terrifying clarity during the flooding by the Mithi river of Bandra-Kurla complex and adjoining low lying areas on July 26-27 2005. As shown by arrows near the Mahim Creek area which trace the Mithi river, mudflats and mangroves were built upon and the river channel reduced to a narrow drain. Since no natural holding areas for the water such as mangroves were left, a combination of high rainfall and high tide led to water level rising up several meters and inundating buildings and even the airport.

But we never seem to understand and learn from history. The same mistakes are being repeated at Panvel and Thane Creeks. When I was growing up, one of the great pleasures of driving to Mumbai from Pune was the gorgeous landscape after Panvel, all those unspoiled tidal channels, creeks and mudflats and mangroves until you crossed the Vasai Bridge. Today that area is an ugly sight. Mud-flats and natural drainages are being filled up and we may soon have constructions coming right up to the banks of the main Panvel tidal channel. The events of July 26 2005 showed how even at present sea-level, bad urban planning can led to severe flooding. The consequences of just one meter rise in sea level can be difficult to predict and may be more damaging than anticipated if you start thinking of its effects on tides and coastal erosion. And add to that are monsoons and storms which may become more powerful as oceans warm up over the century leading to water pileups and storm surges several meters high locally. I really don’t know if the new constructions are being built with future sea-level rise in mind but every time I drive past Panvel all I see is more constructions on those mud-flats. There is no doubt that we are putting the people who will live adjacent to these creeks and channels at a very high risk of flooding and storm damage.