Greenhouse Earth
The greenhouse effect results from a build-up of gases — such as carbon dioxide and methane — in Earth’s atmosphere. CO comes from burning. Burning coal in electric power gen-
2
erating plants. Burning gasoline in car engines. Burning trees in rainforests to clear land for
farming, and from other sources.
Much of the methane, which is 21 times more potent as a greenhouse gas than carbon
dioxide, comes from raising cattle, and growing rice in flooded fields. Cattle release methane
from their bodies, and in their manure. Swamps also generate methane in a natural process. Those gases accumulate in Earth’s atmosphere and act much like the panes of glass in a
greenhouse.
Sunlight passes right through and heats thing up. But
heat gets trapped and cannot escape back into space.
Scientists are seeking solutions, ways to stop and even
reverse the rapidly rising levels of carbon dioxide.
Atmospheric levels of carbon dioxide reached nearly
385 parts per million in 2007, up from 280 in 1850 and
an increase of 2. 6 parts per million from 2006. And we
need new ways of raising cattle and growing rice — staple food for one-third of the world’s population — that
minimize releases of methane. You will hear about some
of those longer-term solutions in Part 2 of this podcast.
Scientists also are working on stopgap measures that can
be put into effect in the short term.
“What’s important to remember about climate change,
in solving it, is that we’re not going to get there tomorrow. We’re starting basically at business as usual. For
all the talk, you know, we haven’t changed anything
in the last 20 years.”
That’s Dr. Frank S. Zeman of Columbia University, an
expert who reported on responses to global warming in
March in Environmental Science & Technology, one of
ACS’s 34 peer-reviewed scientific journals. Some of those
solutions include more energy-efficient buildings, greener
industrial processes, alternative energy sources, improved
fuel-efficient vehicles, and urban planning that encourages mass transit.
Capturing Carbon Dioxide
One of the most promising ways of reducing releases of
carbon dioxide is to capture and sequester, or store, the gas
— lock the gas away so it can’t get out again. Proposals for
CO sequestration include collecting the gas and pumping
2
it down into spent oil or natural gas wells, storing it in the
deep ocean as an icy material, and reacting CO with metal oxides to produce stable carbon-
2
ates. Power plant smoke stacks in the United States alone release almost 2. 5 trillion tons of CO
2
annually. Researchers are looking at several new technologies to capture and eliminate some of
that enormous volume of gas in an economical fashion. Dr. Dianne Wiley, a chemical engineer
with Australia’s University of New South Wales and the Australian Cooperative Center for
Greenhouse Gas Technologies, is one of those researchers.
“I guess the thing to understand with all of these technologies is that those costs are quite
high, particularly if you compare to the European Union estimate for carbon trading,
we should be looking around about the $30 per ton to enable this to be an implementa-ble technology.”
