The global carbon sequestration potential of semi-arid forests is described. Organic and inorganic carbon sequestration were studied in Israel’s planted Yatir forest, a 28 km2 Aleppo pine forest growing at the semi-arid timberline (with no irrigation or fertilization). The organic carbon sequestration rate (above and below ground) was measured as 550 g CO2 m−2 yr−1, by Eddy Covariance flux and Carbon Stock counting methods. Assuming that the soil composition at Yatir is representative, we estimate a global organic sequestration rate of roughly 3.0 billion tons CO2 yr−1, after future global forestation, by extrapolating to 20 % of the global semi-arid area. Consider also the inorganic carbon sequestration rate. A tree’s roots exhale CO2 into the soil after some of the tree’s glucose (produced by photosynthesis) has been oxidized to supply energy for the tree’s cellular processes. The bicarbonate concentration decreases with depth, corresponding to time, as the bicarbonates precipitate and are incorporated within the soil. At Yatir, in 1 Liter of sediment, the calcite precipitation rate was measured as 22 mg CO2 yr−1 L−1. Such calcite remains in place long term, not dissolving in low rainfall semi-arid regions. Taking 6 m as the global average depth of root respiration in semi-arid regions, extrapolating as above, roughly 0.8 billion tons of CO2 could potentially be precipitated globally each year in the USZ as calcite. The total organic plus inorganic sequestration rate of ~4 billion tons CO2 yr−1 then represents roughly 20 % of the present annual increase of 20 billion tons of CO2 being added to the present global atmospheric CO2 reservoir of ~3200 billion tons. Although the uncertainties are high, this estimate already demonstrates the global potential, the need for further measurements, and the need to begin implementing a global land management policy of widespread tree planting in semi-arid regions.
About the speaker:
Murray Moinester, Emeritus Professor of Physics, received his Ph.D. from the University of Rochester in 1968, and then joined the faculty at Tel Aviv University. He served as guest professor for extended periods at many leading universities and accelerator laboratories, has extensive experience in experimental and computational methods, carried out many research programs in high energy particle physics, published some 250 scientific papers in refereed journals, and authored some 75 conference papers. Since retirement, he works in the fields of particle physics, archaeology on infrared spectral imaging & scientific dating, environmental radioactivity, and climate engineering.
Joining the event
This will be a hybrid event, with the opportunity for Imperial staff and students and external guests to attend at one of two campus locations (South Kensington and Silwood Park).
• South Kensington Campus – The Grantham Institute Boardroom, followed by a networking reception.
• Silwood Park Campus – CPB (first floor, Georgina Mace Centre). There will be a livestream followed by a networking reception.
Guests can join the seminar remotely via Zoom. Details to be sent to those who register.
The Changing Planet seminar series is run by students and staff on the Science and Solutions for a Changing Planet (SSCP) Doctoral Training Program. It offers the chance to hear the latest in understanding, adapting to and mitigating environmental problems, complementing the diversity of environmental research at Imperial College London and beyond. Please be aware that our seminars are recorded. If you do not wish to appear on the recording please alert a member of staff. For any further enquiries regarding the Changing Planet seminar series, please contact us at firstname.lastname@example.org .
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