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Ning
Zeng
Associate Professor
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In
the News
Research Opportunities
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My general research interests are in the
field of climate change and climate variability on time scales ranging
from seasonal-interannual to
glacial-interglacial cycles. My approach is to study the Earth system
as a whole, focusing on the interactions among various components, in
particular, the atmosphere, the hydrosphere and the biosphere.
Currently my research covers two different but inter-connected areas:
carbon cycle-climate interaction and the modeling of
atmosphere-land-vegetation-ocean system. I also conduct research in the
technical solutions and policy implications of climate change.
Research Examples
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 Carbon
sequestration via wood burial
To
mitigate global climate change, a portfolio of strategies will be
needed to keep the atmospheric CO2 concentration below a dangerous
level. I propose a carbon sequestration strategy in which certain dead
or live trees are harvested via collection or selective cutting, then
buried in trenches or stowed away in above-ground shelters. The largely
anaerobic condition under a sufficiently thick layer of soil will
prevent the decomposition of the buried wood. Because a large flux of
CO2 is constantly being assimilated into the world’s forests via
photosynthesis, cutting off its return pathway to the atmosphere forms
an effective carbon sink. I estimated that a sustainable long-term
carbon sequestration potential for wood burial is 10 GtC/y. The cost for wood burial is lower than
the typical cost for power plant CO2 capture with geological storage.
The technique is low tech, distributed, easy to monitor, safe, and
reversible, thus an attractive option for large-scale implementation in a world-wide carbon market. Zeng (2008). See Publication for details
and In
the News for media stories and comments.
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 Midlatitude drought and anomalous CO2 growth
A
rare drought occurred from 1998 to 2002 across much of the Northern
Hemisphere midlatitude regions.
Using observational data and numerical models, we analyze the impact of
this event on terrestrial ecosystem and the global carbon cycle. The
biological productivity in these regions were found to decrease by 0.9 PgC/y or 5% compared to the average of the
previous two decades, in conjunction with significantly reduced
vegetation greenness. The drought led to a land carbon release that is
large enough to significantly modify the canonical tropically dominated
ENSO response. This large CO2 source explains the consecutive
large increase in atmospheric CO2 growth rate of
about 2 ppmv/y in recent years, as
well as the anomalous timing of events. Zeng, Qian, Roedenbeck
and Heimann (2005).
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 Glacial-interglacial
Cycles
Only
21,000 years ago, large parts of the Northern Hemisphere were covered
under giant icesheets. Today, the mystery
of the glacial-interglacial cycles remains unsolved. Apart from
important roles astronomical orbital forcing may play, it is becoming
increasingly clear that CO2-climate interaction is a key component.
Zeng (2003) hypothesizes a mechanism in which organic carbon buried
under the icesheets may be a `missing
link' in the ice-age story. Zeng (2007) further proposes a mechanism
where internally generated quasi-100ky cycles could be triggered by subglacial burial carbon release as large icesheets such as the Laurentide
grow long and large enough and the basal melting ejects burial carbon
into the atmosphere, thus starting a carbon-climate-icesheet
feedback that could explain such as the deglaciation
at Termination II.
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 Drought
in the Sahel
The
Sahel, a semiarid
region in West Africa between the Sahara desert and the Guinea
coast rainforest, has experienced an unprecedented drought in recorded
history since the late 1960s. The drought had a devastating impact on
this ecologically vulnerable region and was a major impetus in the
establishment of the United Nations Convention on Combating
Desertification and Drought. In a perspective article in the journal
Science, Zeng (2003) explains our current understanding of the problem.
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