Archive for August, 2007

Biofuels or forests?

Friday, August 31st, 2007

Which has lower greenhouse gas emissions: burning oil or substituting biofuels? It depends in part on what the land might be used for otherwise, but generally it’s the oil, according to an analysis (subscription needed) in the August 17 Science.

Various options for a 30-year period were analyzed. Biofuels can be supplied by land-inefficient methods: sugar cane, sugar beet, or corn to ethanol, for example. Cellulosic biofuels, not yet commercially competitive, use much less land because they use almost all of the plant above the soil. How do these methods compare?

Righelato and Spracklen compared avoided emissions for various crops (sugar cane, wheat, sugar beet, and maize to ethanol, and rapeseed and woody biomass to diesel), and effect of land-use choices on four biomes (tropical and temperate cropland and forest). Afforestration of the same land over 30 years sequesters much greater quantities of carbon, two to nine times as much. The exception was woody biomass in temperate zones, which had comparable benefits.

Whether we use oil or biofuels, improving fuel economy is a must, as is finding ways to get us out of cars and airplanes, experts on both sides of the issue agree.

I will post soon on cellulosic biofuels. If I see a response to this analysis, I’ll post it.

But all but the politicians and farmers agree that
ethanol from corn
ethanol from corn

and from
sugar cane
sugar cane

cannot reduce greenhouse gas emissions significantly in an environmentally friendly manner.

No-analog ecosystems

Wednesday, August 22nd, 2007

Lianas in rainforest
Lianas have been increasing in the rainforest, possibly due to increasing carbon dioxide levels. Lianas are parasites, increasing tree mortality and decreasing the amount of carbon stored. Climate change is also altering rainforest ecosystems.

When the climate changes, naturally or not, species move. It is already known that species are moving at different speeds, that ecosystems are not traveling together. New reports indicate that the ecosystems of the future may not simply be the loss of high latitude and altitude ecosystems, and their replacement by other ecosystems; these may look very different in 2100.

The May 11 Science (subscription required) describes no-analog ecosystems, such as forests of spruce, sedge, oak, ash, and hophornbeam, that once existed but do not today — there is no analog today. A sizable percentage of the Earth may be covered by these no-analog ecosystems in 2100.

First, much of the Earth will have combinations of summer and winter temperatures and precipitation patterns that we don’t see anywhere today. The tropics and subtropics are most likely to see these novel climates. On top of that, climates we do recognize will require too much travel by plant species to end up with today’s distribution. Connecting reserves to facilitate species shift won’t be enough.

Limiting the analysis to four variables — summer and winter mean temperature and precipitation — and two scenarios (B1, or low, and A2, or high) produced dramatic changes:

[B]y 2100, depending on which climate scenario and model they use, 4% to 39% of the world’s land area will experience combinations of climate variables that do not currently exist anywhere on the globe. Areas with these novel climates are likely to develop no-analog ecosystems.

A 2005 study included more variables, such as soil type, and found more profound changes.

Assuming that ecosystems can migrate at most 500 km, 300 miles, in a century, the recent study found 14 – 85% of the Earth will be covered by no-analog ecosystems.

A number of variables, such as extremes in temperature and fire frequency, were ignored; we can assume estimates are conservative.

The prospect of novel climates has people rethinking traditional goals such as maintaining native ecosystems. “That’s probably going to be impossible,” says Nathan Stephenson, a research ecologist at the USGS Western Ecological Research Center in Three Rivers, California. “But what you can still do, even if you can’t maintain native communities, is potentially maintain regional biodiversity and ecosystem functions.”

This too will be challenging.

Green chemists in Ethiopia

Wednesday, August 15th, 2007

Also in the June 29 Science, an article looks at Ethiopian research into more environmentally acceptable solvents to replace petroleum-based ones, in a country without oil. Ethiopia does have a few advantages:

intense sunlight, unique plant species, and enthusiastic young people

Two researchers
A collaboration was born when two researchers met: Martyn Poliakoff (left), from Nottingham, was on holiday in Ethiopia and Nigst Asfaw (right), a lecturer at Addis Ababa University, was looking for a research theme.

A new dawn for science in Africa

Wednesday, August 15th, 2007

Science in Africa
Science in Africa

A few years ago, Science and Nature magazines talked about scientific cooperation between the first and third world. Later, the talk morphed to letting third world scientists have more say in topics chosen.

Now Mohamed Hassan, head of TWAS (Academy of Sciences for the Developing World) has authored an editorial in the June 29 Science describing shifts in African investments in science and technology in Africa.

Rwanda is now spending 1.6% of its GDP, and wants to increase this to 3% within 5 years.

Nigeria plans a national science foundation.

Uganda and Zambia, with loans from the World Bank and African Development fund, will fund research and postgraduate students.

South Africa woman of the year 2004
South Africa woman of the year 2004, science and technology category

South-south cooperation has helped this to occur. Brazil, China and India have increased their own science programs, and are now helping fund research in Africa. China has invested $5 billion in Development Fund for Africa to help countries meet the United Nations Millennium Development Goals. Brazil supports science and technology programs in sub-Saharan Africa, particularly in (Portuguese-speaking) Mozambique and Angola. India and Brazil are (surprise!) working on biofuels projects with Africans.

international journal covering all African waters
international journal covering all African waters

See Hassan’s plenary presentation to the 2007 American Association for the Advancement of Science.

Also check out the Africa Science blog.

African countries cannot afford political interference in science (nor can any of us). Perhaps 900 South Africans die daily from AIDS-related illnesses.

Nozizwe Madlala-Routledge
Deputy Health Minister Nozizwe Madlala-Routledge was fired by President Mbeki because she was not a good team player with someone who advocates treating AIDS with garlic.

Our Future: Asia

Wednesday, August 15th, 2007

Packages from relief helicopters
Packages from relief helicopters

I haven’t posted on the recent flooding in Asia in part because I was out of town when the floods started, in part because of the enormous humanitarian disaster. It’s easier emotionally to focus on a few coal miners than the millions. A larger part though is the fear that this is their future.

Wading through floodwaters
Wading through floodwaters Health, food, and agriculture are concerns.

As of today, more than 2,000 are dead, and more than 30 million have lost homes or/and livelihoods. That is 10% of the US population.

There have been costlier floods. The Yellow River in China flooded in 1931, killing hundreds of thousands or millions. During the 20th century, many millions of Chinese died from floods.

Floods have killed for years. In the Netherlands in 1228, 100,000 died after dykes broke.

Bangladesh, which will see increasing problems over the next few decades, suffered major floods in 1970 (200 – 500,000 dead) and 1991 (more than 100,000 dead).

In North Korea between 1995 and 1998, millions died from famine and floods. In the recent floods in North Korea, good agricultural land was affected, and crops will be lost. It isn’t just those who die immediately from the floods, but crops that are destroyed.

From IPCC, 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change:

Since 1950, the number of heat waves has increased and widespread increases have occurred in the numbers of warm nights. The extent of regions affected by droughts has also increased as precipitation over land has marginally decreased while evaporation has increased due to warmer conditions. Generally, numbers of heavy daily precipitation events that lead to flooding have increased, but not everywhere. Tropical storm and hurricane frequencies vary considerably from year to year, but evidence suggests substantial increases in intensity and duration since the 1970s. In the extratropics, variations in tracks and intensity of storms reflect variations in major features of the atmospheric circulation, such as the North Atlantic Oscillation.

Will it get worse?

[T]he type, frequency and intensity of extreme events are expected to change as Earth’s climate changes, and these changes could occur even with relatively small mean climate changes…Along with the risk of drying, there is an increased chance of intense precipitation and flooding due to the greater water-holding capacity of a warmer atmosphere. This has already been observed and is projected to continue because in a warmer world, precipitation tends to be concentrated into more intense events, with longer periods of little precipitation in between. Therefore, intense and heavy downpours would be interspersed with longer relatively dry periods…

In particular, over [Northern Hemisphere] land, an increase in the likelihood of very wet winters is projected over much of central and northern Europe due to the increase in intense precipitation during storm events, suggesting an increased chance of flooding over Europe and other mid-latitude regions due to more intense rainfall and snowfall events producing more runoff. Similar results
apply for summer precipitation, with implications for more flooding in the Asian monsoon region and other tropical areas. The increased risk of floods in a number of major river basins in a future warmer climate has been related to an increase in river discharge with an increased risk of future intense storm-related precipitation events and flooding. Some of these changes would be extensions of trends already underway.

Samson by Diane Gilliam Fisher

Thursday, August 9th, 2007

Pillars is the walls of coal you leave
between rooms while you working
the rooms
Boss had me explain it
to the Big Boss come down from Boston
on the train to lay eyes on things.
Boss didn’t call me by my name,

just holler, Come on over here, son.
Bragged how big I is, how strong
a colored boy get when he shovel and haul.
Didn’t ask me how my eye got gone?
coal shot out when I was pillar-drawing.
Didn’t ask my name, neither one.

I played along. Yessir, I told them,
them pillars is coal, they can get sold.
We come back in when the rooms is all mined
and pull them down, we don’t leave nothing
behind. I’ve knowed three men’s died that way,
nothing left of them but their names

roof don’t hold too long without no walls.
Bosses begin to edge back toward the hall.
I stood in their way. With my right hand
I pressed one pillar, the other with my left.
I explained To the mountain we all the same.
I pressed harder, and I told them my name.

I found this poem at Of Appalachia and Coal Miners: in memory of those killed in coal mining accidents in January, 2006. Let us hope that the coal miners in Utah do better.

What is your favorite coal mining poem?