Geo-engineering Not the Answer. So what about Nitrogen?

A team of British academics will
undertake the world’s first major ‘geo-engineering’ field test in the next few
months. It’s atmospheric liposuction: a retrospective fix for planetary
over-indulgence, says George Monbiot.
Geo-engineering, which means either sucking carbon dioxide out of the
atmosphere or trying to shield the planet from the sun’s heat, is an admission
of failure, a failure to get to grips with climate change. But is nitrogen the
answer? Researchers have discovered that forest trees can tap into the nitrogen
found in rocks, boosting their growth and allowing them to take up more carbon
dioxide from the atmosphere.

George Monbiot

guardian.co.uk, Friday 2 September 2011

A team of British academics will
undertake the world’s first major ‘geo-engineering’ field test in the next few
months

It’s atmospheric liposuction: a
retrospective fix for planetary over-indulgence. Geo-engineering, which means
either sucking carbon dioxide out of the atmosphere or trying to shield the
planet from the sun’s heat, is an admission of failure, a failure to get to
grips with climate change. Is it time to admit defeat and check ourselves into
the clinic?

The question has arisen again
with the launch of a new experiment funded by Britain’s Engineering and
Physical Sciences Research Council, injecting particles (in this case water
droplets) into the atmosphere from a gigantic balloon attached to a hosepipe.
The eventual aim, if such experiments are deemed successful, is to squirt large
amounts of sulphate aerosols into the stratosphere, to reduce global warming by
scattering sunlight back into space.

There are five issues affecting
all the proposed geo-engineering technologies. Are they effective? Are they
cheap? Are they safe? Do they solve the other problem associated with rising
greenhouse gas emissions: ocean acidification? Do they introduce moral hazard?
(This means the risk that you’ll behave more recklessly if you’re insulated
from the effects of your actions.)

Broadly speaking, the cheap and
effective options are dangerous; the safe options are expensive or useless.
This isn’t always the case. Seeding the oceans with iron filings, for example,
is probably both useless and dangerous. The intention is to stimulate a bloom
of algae which absorbs carbon dioxide then sinks to the ocean bed. Not only is
little of the gas removed from surface waters by this method; but, because the
iron mops up oxygen, it stimulates the production of methane, a potent greenhouse
gas. The technique is likely both to damage life in the oceans and cause more
global warming than it cures.

There are dozens of proposed
techniques. Here’s a small sample: Sucking CO2 out of the air using artificial
trees. Safe. Effective. Fantastically expensive.

Growing biomass then burying it
or dumping it in the sea. Ecologically damaging. Likely to exacerbate famine.
Ineffective (because it can’t be scaled up sufficiently). Fairly cheap.

Dumping lime or calcium or
magnesium silicates into the sea, where they react with carbon dioxide. Fairly
safe. Effective. Expensive. Has the advantage of potentially reversing ocean
acidification, but the amount of quarrying required to produce enough ground-up
rock is likely to be prohibitive.

Painting buildings white to
ensure that the earth absorbs less of the sun’s heat. Safe. Useless. Expensive.

Whitening clouds to reflect more
sunlight, most feasibly by spraying salt water into the air. Middling
dangerous. Middling useless. Middling cheap.

Shooting mirrors into space. Not
very dangerous. Effective. Staggeringly expensive.

You can read more detailed
summaries of these options in a report published by the Royal Society.

But of all techniques, it’s the
notion of injecting reflective particles into the atmosphere – the technique
the balloon and hosepipe experiment is designed to test – that has received
most attention. There’s an obvious reason for this: it is both cheap and
effective. It is also extremely dangerous.

The reason seems almost as
incredible as the proposed technologies, but it’s rooted in solid science. In
fact we’ve already tested the method at a very large scale, with catastrophic
results. Unfortunately no one realised we were running the experiment until
three decades after it began.

It wasn’t until 2002 that a paper
was published linking the great famines of the 1970s and 1980s with atmospheric
sulphate particles produced in the northern hemisphere. But the link, which has
now been made in a number of papers, listed below, seems to be conclusive:

LD Rotstayn and U Lohmann, 1
August 2002. Tropical Rainfall Trends and the Indirect Aerosol Effect. Journal
of Climate, vol 15, pp2103-2116

IM Held, TL Delworth, J Lu, KL
Findell, and TR Knutson, 13 December 2005. Simulation of Sahel drought in the
20th and 21st centuries. PNAS, vol 102, no 50, pp17891-17896. DOI:
10.1073/pnas.0509057102

M Biasutti and A Giannini, 8 June
2006. Robust Sahel drying in response to late 20th century forcings.
Geophysical Research Letters, vol 33, no 11. DOI: 10.1029/2006GL026067

JE Kristjansson et al, 23
December 2005. Response of the climate system to aerosol direct and indirect
forcing: Role of cloud feedbacks. Journal of Geophysical Research –
Atmospheres, vol 110, no D24

By reducing the size of the
droplets in clouds, thereby ensuring that they reflected more light (which is
the desired outcome of the current experiment), the sulphate particles lowered
the temperature of the sea’s surface in the northern hemisphere. The result was
to shift the Intertropical Convergence Zone – a region close to the equator in
which moist air rises and condenses into rain – southwards. The Sahel, which
covers countries such as Ethiopia, Sudan, Chad, Niger, Burkina Faso and
Senegal, is at the northern limits of the zone. As the rain belt was pushed
south, the Sahel was left high and dry. As a result of the clean air acts,
between 1970 and 1996 sulphur emissions in the US fell by 39%. This appears to
have helped the North Atlantic to warm, allowing the rains to return to the
Sahel in the 1990s.

The balloon and hosepipe
experiment is a complete waste of time. The hazardous effects of injecting
particles into the atmosphere are unlikely to make themselves known until the
technique is deployed on a very large scale and for several years. The impacts
of small-scale tests will be lost in the noise of global weather. A full-scale
experiment would be, to say the least, unethical.

As a recent paper in Nature
Geoscience points out, it is “physically not feasible” to stabilise
global rainfall and temperature by means of this technique while greenhouse gas
emissions are still rising. The effects of shooting particles into the
atmosphere will vary dramatically in different parts of the world, helping
some, harming others. It’s impossible to see how the countries likely to be
harmed by this technique would agree to it. If it were imposed on them it would
lead to the mother of all conflicts – and the mother of all lawsuits.

It is so obvious that this
approach is a non-starter that the £1.6m the UK government is spending on the
experiment would be better used to investigate those age-old questions of how
to turn lead into gold or extract sunshine from cucumbers.

This is not to suggest that we
should dismiss all geo-engineering techniques out of hand. But, like liposuction,
none of those being proposed are simultaneously safer, cheaper and more
effective than addressing the problem at source. This means reducing our
greenhouse gases. A good diet and plenty of exercise are better than the knife.

Source: www.guardian.co.uk

Posted on September 1, 2011 -
03:53 by Emma Woollacott in TG Daily

Researchers have discovered that
forest trees can tap into the nitrogen found in rocks, boosting their growth
and allowing them to take up more carbon dioxide from the atmosphere.

The nitrogen in rocks could
therefore significantly affect how rapidly the Earth warms in future, says the
University of California, Davis team.

“We were really shocked;
everything we’ve ever thought about the nitrogen cycle and all of the textbook
theories have been turned on their heads by these data,” says
biogeochemist Professor Benjamin Houlton.

“Findings from this study
suggest that our climate-change models should not only consider the importance
of nitrogen from the atmosphere, but now we also have to start thinking about
how rocks may affect climate change.”

It was previously believed that
nitrogen could only enter ecosystems from the atmosphere – either dissolved in
rainwater or biologically ‘fixed’ by specialized groups of plants and other
organisms.

However, says the team, there’s
enough nitrogen contained in one inch of the rocks at the study site to
completely support the growth of a typical coniferous forest for about 25
years.

“This nitrogen is released
slowly over time and helps to maintain the long-term fertility of many
California forests,” says biogeochemist
Professor Randy Dahlgren.

In fact, forests growing on
nitrogen-rich rock were about 50 percent more productive than those growing on
nitrogen-poor rocks throughout Northern California and into Oregon.

The researchers found that the
nitrogen isotopes in the rock matched those of the soils and trees, confirming
that the nitrogen was coming from the rocks.

“It was like a fingerprint;
we found the culprit, and it was the nitrogen in the rocks,” says graduate
student Scott Morford.

Since nitrogen tends to be
highest in sedimentary rocks – which cover roughly 75 percent of the Earth’s
land surface – the discovery has tremendous global significance, says the team.

“The stunning finding that
forests can also feed on nitrogen in rocks has the potential to change all
projections related to climate change,” says Houlton.

“This discovery may also
help explain several other studies that have found that the nitrogen ‘budgets’
of forests are out of balance, the nitrogen accumulation in their soil and
plants being substantially greater than the apparent nitrogen inputs.”

Researchers now include nitrogen
in their climate-change models, and some indicate that it could cause an
additional increase in global temperatures of up to 1.8 degrees Fahrenheit, as
it limits the amount of carbon dioxide that plants can extract from the
atmosphere.

If more nitrogen is available
than predicted from the traditional nitrogen-cycling pathways, as the UC Davis
study suggests, it could lead to more carbon storage on land and less carbon
remaining in the atmosphere.

Source: www.tgdaily.com