By Liz Kalaugher
Field work can be tough – especially when there’s no power, bad roads and your transect line is too steep to use your favourite measurement methods. That’s what happened to YIt Arn Teh of the University of St Andrews, UK, when he studied methane and nitrous oxide fluxes in the Kosñipata Valley in Manu National Park, southeastern Peru.
As Teh explained in a talk at the EGU meeting, the gradient of much of his route, which started at an altitude of 3500 m and headed down to the Amazon basin, was too steep to use Eddy covariance sampling. Nothing daunted, Teh went “back to basics” and used chambers to gather his data.
Teh was hunting for the “missing” sources and sinks in the tropics that regional atmospheric budget discrepancies indicate might be located in South America.
Along his transect lay Puna grasslands at the top of the mountain, cloudforest at around 2800 m, then mid-elevation forest followed by foothills.
The findings? Altitude had a massive effect. At lower elevations the ecosystems were a sink for methane, but at higher elevations they acted as a methane source. The situation for nitrous oxide was more complex – low, mid and high elevations acted as a source, but the cloudforest at around 2800 m acted as a sink for the gas.
Now Arn Teh would like to work with colleagues in modelling and remote sensing to build on these findings.
By Liz Kalaugher
The thousands of delegates congregating in Vienna this year will find the EGU making further efforts to “green” the meeting – badge lanyards are made from bamboo fibre rather than PET and the conference schedule is smaller to save paper. It seems only appropriate, since many of the sessions at the conference will focus on the cryosphere (shrinking), climate (warming), natural resources (under pressure) and energy. But are such measures just a drop in the ocean, especially as environmental issues appear to have fallen down the priority list for many governments?
Indeed, governments received a call for action within the first half hour of the conference opening, with Millie Basava-Reddi of the International Energy Agency Greenhouse Gas R&D programme (IEAGHG) stressing the need for investment in carbon storage, in her talk presented by session chair Michael Kühn due to a delayed flight.
While the G8 nations would like to see 20 carbon capture and storage projects up and running by 2020, the IEA target is 100 by 2020 and 3,400 by 2050. The agency’s latest assessment, however, indicates that while 20 projects are feasible for 2020 its own roadmap isn’t, with just 50 projects likely by 2025. Worldwide there are currently 14 large-scale integrated projects in operation or execution; 2011 saw 74 large-scale projects in at least the planning stage. Basava-Reddi called on governments to allow for long project lead times – up to fifteen years – and to help to provide up-front investment.
The challenges for carbon capture and storage in many cases mirror those for other subsurface technologies such as geothermal energy. Indeed Kühn’s group at the Helmholtz Centre Potsdam, Germany, is researching how brine extraction from saline aquifers could help reduce the pressure rise induced by the addition of carbon dioxide, whilst at the same time providing geothermal heat.
There are a large number of issues in geothermal energy that need substantial research efforts, explained Adele Manzella of CNR Institute for Geosciences and Earth Resources, Italy. The upper 3 km of the Earth’s crust could provide 60,000 times our current power consumption; the only snag is where and how to access that power. The up-front costs are high and it’s hard to forecast production, especially since there is a lack of data on geothermal potential. But once systems are set up the energy produced is cheap compared with other types of renewable energy, since power is provided 24 hours a day.
The European Energy Research Alliance has set up a Joint Programme on Geothermal Energy, said Manzella. Areas under study include assessing Europe’s resources for geothermal power, how to mitigate induced seismicity in reservoirs, and high-performance drilling.
I agree with some prognosticators that attribute all global warming to natural processes. From normal cycles of the atmosphere to the regular Earth orbit and wobble about its axis. From sunspots to wildfires, natural processes dominate the flux of carbon dioxide and other greenhouse gases into and out of the atmosphere. But there is one natural process that is usually categorized incorrectly: the actions of that species that is Homo sapiens.
H. sapiens, or we humans, follow the same trend as many other animal species in discovering food and energy resources and using them to proliferate and maintain numbers. However, we have a seemingly innate ability to acquire knowledge and pass it on to younger generations such that the subsequent H. sapiens don’t have to “reinvent the wheel” every generation. This accumulation of knowledge began with the first writing, continued with the teaching of agriculture for stable food supplies, and is now culminating in the transfer of information (and much of it simply data or low-value information) across the internet as is occurring when you are reading these words.
The process of accumulating knowledge, using that knowledge to create even further new knowledge of how to make new tools and extract and use natural resources has been occurring for approximately 10,000 years. Over this time, we have discovered laws of physics, incredibly advanced the science of medicine, and established societal laws and governmental structures. All the while we H. sapiens expand in population (with a few bumps in the road due to disease) and extract more renewable and fossil resources from the Earth each year. H. sapiens is a part of this Earth just as much as are Oncorhynchus mykiss (rainbow trout), Gorilla gorilla (Western Gorilla), and Sequoiadendron giganteum (Giant Sequoia). Granted, the trees have a hard time extracting resources beyond their roots, and the trout don’t have opposable thumbs that allow them to grasp rocks in the stream bed to make houses or fish pens. G. gorilla have thumbs but don’t seem able to venture out far from their original habitat. Most plant and animal species simply expand when resources (prey, nutrients, sun, rain, etc) are abundant and contract when they are scarce – simply a response to immediate stimuli. But those darn H. sapiens make clothing and shelter that allows them to stay in climates and conditions for durations that would otherwise kill them. This learned planning ability to plan ahead for the future seasons and years has been used to further the natural expansion and reach of humans across all continents of the globe.
With these thoughts in mind, why call anything done by us humans to date anything other than “natural”? We don’t make steel, we find iron ore and carbon-containing substances to combine them when heated to form a substance with new properties we call steel. Using steel and other transformed materials we assemble objects, composed of many of these refined and purified substances, that would otherwise not exist on Earth. But oysters do the same thing in constructing their shells. We just do it a lot more, a lot faster, and into more materials.
If we consider the terms “man-made” and anthropogenic as describing actions that go against the continued expansion of Homo sapiens, then what past decisions can fall into that category? Two candidates come to mind: (i) the Chinese one-child policy and (ii) the OPEC/Arab Oil embargoes of the 1970s. it In restricting the spreading of a sixth of the world population, the one-child policy is meant more to preserve the Chinese state more than the humans in general. But don’t short-change the one child policy as being a possible climate policy – as was suggested by some at the recent Copenhagen talks.
And the oil embargos, in hindsight, could be considered the first greenhouse gas policy and/or energy conservation policy. By restricting the flow of resources to a large part of H. sapiens, the leaders of a few resource-rich countries triggered a drastic change in the growth of energy consumption of the world, and hence greenhouse-gas emissions. Annual growth in world energy consumption was increasing close to exponentially until the 1970s, and after that it has been growing only linearly (i.e. at a slower rate). We could possibly attribute 100s of exajoules (or quads) of annual energy conservation to OPEC.
Perhaps embargoes and tariffs in general are a truly man-made construction. The one-child policy and oil embargoes were targeted with the intention of preserving the wealth/power of certain political entities – one with some intent to punish other political entities. Political states being the result of increasing complexity in society, they are inherently man-made. Thus, organization by treaty and by writing is man-made. And perhaps that is why negotiating a limit on greenhouse gas emissions was not successful in Copenhagen this December – because such a limit is a man-made restriction of a natural tendency, not a natural restriction of an anthropogenic tendency.
A recent study, summarized here, described the Gamburtsev Mountains in the heart of East Antarctica. This buried landscape exhibits many of the classical results of alpine glaciation, including cirques – great bowl-shaped hollows carved out of mountainsides by glaciers – and overdeepened valleys.
The work may have begun as early as 34 million years ago, when records from elsewhere show that ice began to accumulate in Antarctica in significant amounts. But the bowl-shaped hollows are still there. Ice sheets are about 2000 km across, and they don’t carve bowl-shaped hollows that are only about 5 km across. So the cirques were probably shaped more than 14 million years ago, which is when we think the ice in Antarctica grew to continental proportions. If this is right, the ice must have shifted from carving up the bedrock surface to protecting it.
We don’t know when the Gamburtsev Mountains were first lifted up. The dates just given are from indirect reasoning. On the other hand, the glaciation of Antarctica had to start sometime, somewhere, and a preglacial mountain range not far from the South Pole sounds like a good nucleus. But there is more missing from the story than just the age of the Gamburtsevs.
First, whether mountainous or not, there has been an extensive landmass over the South Pole for much longer than 34 million years. Motions due to plate tectonics brought Antarctica to roughly its present position almost 100 million years ago, yet it seems to have enjoyed a benign climate for the first 60 or more million years of that span. The switch from benign to cool and then frigid could well have been triggered by the uplift of the Gamburtsevs, or possibly of the more extensive Transantarctic Mountain Range, but in the one case we have no evidence as yet and in the other the uplift has been going on for even longer than 100 million years.
Second, this is a good excuse for me to tell you about the widely-unread paper I published 25 years ago about the subglacial topography of Antarctica. Developments since then have not altered the main conclusion: if you take away the ice that now covers East Antarctica, and allow the bed to rebound from the load of 3 to 4 km of ice, you get a rather unusual preglacial continent. This ice-free East Antarctica of the geomorphologist’s imagination is a full 700 m higher than all of the continents we know today (except that it is only 500 m higher than Africa – but that is another story). We are not talking about a single mountain range here. This is the whole continent, or in other words a broad plateau cooler than a normal continent would have been by perhaps 4°C.
Unfortunately, we don’t know when Antarctica became an elevated plateau, any more than we know when the Gamburtsev Mountains first appeared. There are far too many ifs in the story of Antarctic topography and glaciation. That is a strong argument for reducing the number of ifs, but lurking in the background there is a familiar friend: the greenhouse effect.
Less greenhouse gas in the atmosphere would account for all of the evidence that Antarctica has been getting colder for several tens of millions of years. The evidence that the greenhouse effect has been diminishing for a long time is in fact extremely good. One, or to be more accurate Bob Berner of Yale University, does a detailed accounting of all the carbon in the rocks, and uses the book-keeping to drive calculations of how the carbon would have passed to and fro between the various stores, such as the Earth’s deep interior, the biosphere and the atmosphere. The atmospheric stock, nearly all of it carbon dioxide, was about five times its present size 100 million years ago. (Why so? That is yet another other story.)
The more diverse the facts that a hypothesis succeeds in explaining, the more do we respect it. The long-term cooling of Antarctica is not as remote from our 21st-century concerns as it sounds. In fact the same explanation holds for the climate of Antarctica over the past 100 million years as for the temperatures we have measured over the past 100 years and the temperatures we expect over the next 100 years. Greenhouse gas makes our home warmer.