Global Challenges/Chemistry Solutions

Global Climate Change: The Quest for Permanent Solutions

Environmental Science & Technology

February 27, 2009

Summary

Today’s topic is research on global climate change.
This discovery could help control the amount of
carbon dioxide — the No. 1 greenhouse gas —
entering the atmosphere. Scientists in Washington
and California have studied a way to permanently
sequester, or isolate, CO2 from the environment.

Burial at Sea for CO2

Imagine a massive international effort to combat global warming by reducing the build-up of carbon dioxide in the atmosphere. It involves gathering billions of tons of cornstalks, wheat straw, and other crop residue from farm fields. Those plants remove carbon dioxide — CO2 — from the atmosphere during photosynthesis. It becomes part of the plant tissue.

However, the CO2 goes right back into the atmosphere when the plants decompose. So you take all crop residue with its CO2, and bail it up like hay. Then you ship it to seaports, and bury the residue and the carbon dioxide in the deep ocean.

Scientists in Washington and California have studied this way to permanently sequester, or isolate, CO2 from the environment. Stuart Strand and Gregory Benford and colleagues call it CROPS. That’s Crop Residue Oceanic Permanent Sequestration. They conclude that CROPS is the only method available right now to sequester huge amounts of carbon dioxide. From the University of Washington in Seattle, here is Dr. Strand:

“The essence of our work is to place these crop residues –
these bails of straw – in the deep ocean sediment, and this
is the region of the earth where the fossil fuel carbon
originated. We removed it from the sediments as oil and
coal, and we want to put it back in the sediments because
they’re deep in the ocean, separated from the atmosphere
by the stratification of the ocean – the upper and lower
ocean don’t mix very well, so if we put it in deep enough
water even if it does oxidize, the CO2 that’s produced will
not mix with the upper ocean and be in contact with the
atmosphere for at least 1,000 years.”

CROPS is Tops

In a report in ACS’ journal Environmental Science & Technology, Strand’s team compared methods for carbon dioxide sequestration based on efficiency, long-term effectiveness, practicality, and cost. CROPS was tops. They concluded that CROPS could reduce global carbon dioxide accumulation by up to 15 percent per year. That amounts to millions of tons of carbon dioxide.

“So that’s about 600 megatons of CO2 carbon per year,
so each year it could be repeated, and 600 megatons
of CO2 carbon would be removed permanently from the
atmosphere.”

Dr. Strand and his colleagues cite the need for research on CROPS’ environmental impact on ocean sediments. If that impact is acceptable, CROPS from a scientific standpoint, would be good to go.

Smart Chemists/Innovative Thinking

Smart chemists. Innovative thinking. That’s the key to solving global challenges of the 21st Century. Please check our full-length podcasts on stopgap [Confronting Climate Change] and permanent solutions [Confronting Climate Change II] to this daunting problem. Today’s podcast was written by Michael Woods. I’m Adam Dylewski at the American Chemical Society in Washington.

Further reading:

Environmental Science & Technology
“Ocean Sequestration of Crop Residue Carbon: Recycling Fossil Fuel Carbon Back to Deep Sediments”