SCIENCE science.orgBy Ruth DeFries 1,2, Richie Ahuja^3 , Julio
Friedman4,5, Doria R. Gordon3,6, Steven P.
Hamburg^3 , Suzi Kerr^3 , James Mwangi7, 8,
Carlijn Nouwen^7 , Nitin Pandit^9D
emand for credits on the voluntary
carbon market is poised to surge as
corporations implement net-zero
commitments. Approximately half of
all credits issued from 2000 to 2021
on the voluntary carbon market re-
lated to land use, mostly from forest proj-
ects (fig. S1) ( 1 ). Credits from the land sec-
tor pose challenges for accounting and for
meeting multiple criteria. We propose three
pathways to overcome shortcomings in the
carbon market, improve integrity of credits,
and promote long-lasting change to achieve
nontrivial climate mitigation and co-benefits
from the land sector: (i) target major sources
of land-based emissions by increasing ac-
tivities that reduce or avoid non-CO 2 green-
house gas (GHG) emissions; (ii) promote
longevity of low-GHG land management by
ensuring that locally relevant co-benefits ac-
crue to local land users; and (iii) encourage
region-wide over individual project-based
activities to promote systemic change, pro-
vide equitable access to benefits, enable real-
istic accounting, and scale opportunities for
emissions reductions.
Agriculture, forestry, and land use account
for ~20% of global anthropogenic GHGs
(from enteric fermentation in livestock and
manure, agricultural soils, crop burning, de-
forestation, cropland degradation, and rice
cultivation in decreasing order of emissions)
( 2 ). Reducing emissions from this sector is
essential to address the goals of the Paris
Agreement. In addition, restoration and im-
proved management of multiple types of eco-
systems can provide opportunities to remove
carbon from the atmosphere and store it in
the biosphere, although the magnitudes areuncertain and potential land conflicts raise
serious concerns. Estimates indicate that up
to 60% of emissions from agriculture rela-
tive to 2030 business-as-usual projections
and 110% of emissions from the forestry sec-
tor are technologically and economically fea-
sible to reduce ( 3 ).
Multiple approaches can economically
incentivize reduced emissions and carbon
sequestration from land management, in-
cluding fines for violating regulations, sub-
sidies and tax credits, capped emission in
cap-and-trade programs, and payments. All
of these approaches can play a role in a tran-
sition to low-GHG land management. The
current net-zero commitments and explosive
growth in the voluntary carbon market of-
fer an unprecedented opportunity to bringfinance to the land sector for mitigating cli-
mate change, if criteria and accounting can
overcome problems of low integrity and in-
equitable benefit sharing.
The integrity of land-based credits in the
voluntary carbon market has been histori-
cally uneven. Buyer confidence can only oc-
cur with high-integrity credits—in other
words, assurance that credits represent doc-
umented, actual reductions, avoidance, or
removal of GHGs that would otherwise not
occur. This integrity needs to improve sub-
stantially for these types of investments to
effectively reduce GHG emissions or remove
them from the atmosphere in voluntary car-
bon markets.
Multiple factors contribute to low confi-
dence in carbon market credits, including
difficulties with assurances of additionality
(whether interventions to reduce emissions
or store carbon would occur in the absence
of revenue from the carbon market), per-
manence (the integrity of how reversed
benefits of avoided or stored emissions areaddressed), leakage (whether reductions
in one place are displaced by emissions to
another place), and quantification (whether
reductions are accurately quantified relative
to an appropriate baseline and reported).
Another factor contributing to low confi-
dence is the potential for displacement and
inequitable benefit sharing with marginal-
ized and Indigenous peoples in places with
conflicts between customary and statutory
land tenure, asymmetric power relations, or
poor governance. Such negative outcomes
have occurred with previous implementa-
tion of financing for forest-based climate
mitigation ( 4 ).
In the absence of improved integrity, car-
bon markets are likely to shift toward proj-
ects that buyers perceive as higher quality,
such as long-term geologic storage from
carbon capture and storage, that more easily
meet the criteria. Without alternative path-
ways to improve integrity of credits from the
land sector, opportunities for the sector to
contribute to cost-effective climate mitiga-
tion and its potential co-benefits for biodiver-
sity and local livelihoods could be negated.NON-CO 2 GHGS
The Sixth Assessment of the Intergovern-
mental Panel on Climate Change highlights
the opportunity to reduce non-CO 2 GHGs,
particularly methane (CH 4 ), as a mecha-
nism to reduce the rate of warming over
the near to medium term and provide re-
lief from climate change. Land-based activ-
ities are substantial anthropogenic sources
of non-CO 2 GHGs, which drive the bulk of
warming between now and 2050. Enteric
fermentation, manure, and rice cultivation
together emit more CH 4 than fossil fuels,
and agriculture emits roughly four times
as much nitrous oxide (N 2 O) as fossil fuels
(table S1). Until the recent pledge to reduce
CH 4 emissions from a diversity of sectors
by 30% by 2030, adopted by more than a
hundred countries at the 26th Conference
of Parties in Glasgow, there has been no
systematic effort to drive down these criti-
cal non-CO 2 emissions.
Currently, credits issued and number of
projects in the voluntary carbon market
are overwhelmingly related to projects that
avoid or reduce CO 2 emissions or sequesterCLIMATE CHANGELand management can contribute to net zero
POLICY FORUM
(^1) Department of Ecology, Evolution, and Environmental
Biology, Columbia University, New York, NY, USA.
(^2) Climate School, Columbia University, New York, NY, USA.
(^3) Environmental Defense Fund, New York, NY, USA. (^4) Center
for Global Energy Policy, Columbia University, New York, NY,
USA.^5 Carbon Direct LLC, New York, NY, USA.^6 Department
of Biology, University of Florida, Gainsville, FL, USA.^7 Climate
Action Platform Africa, Nairobi, Kenya.^8 Dalberg Group,
Nairobi, Kenya.^9 Independent consultant, Vienna, VA, USA.
Email: [email protected]
The voluntary carbon market needs to embrace changes for the land sector
“A shortcoming of the current
project-based carbon
market is its small-scale,
piecemeal approach
through individual projects.”
10 JUNE 2022 • VOL 376 ISSUE 6598 1163