<p class="first" id="d3729468e137">Nature-based solutions (NbS) can address climate
change, biodiversity loss, human
well-being and their interactions in an integrated way. A major barrier to achieving
this is the lack of comprehensiveness in current carbon accounting which has focused
on flows rather than stocks of carbon and led to perverse outcomes. We propose a new
comprehensive approach to carbon accounting based on the whole carbon cycle, covering
both stocks and flows, and linking changes due to human activities with responses
in the biosphere and atmosphere. We identify enhancements to accounting, namely; inclusion
of all carbon reservoirs, changes in their condition and stability, disaggregated
flows, and coverage of all land areas. This comprehensive approach recognises that
both carbon stocks (as storage) and carbon flows (as sequestration) contribute to
the ecosystem service of global climate regulation. In contrast, current ecosystem
services measurement and accounting commonly use only carbon sequestration measured
as net flows, while greenhouse gas inventories use flows from sources to sinks. This
flow-based accounting has incentivised planting and maintaining young forests with
high carbon uptake rates, resulting, perversely, in failing to reveal the greater
mitigation benefit from protecting larger, more stable and resilient carbon stocks
in natural forests. We demonstrate the benefits of carbon storage and sequestration
for climate mitigation, in theory as ecosystem services within an ecosystem accounting
framework, and in practice using field data that reveals differences in results between
accounting for stocks or flows. Our proposed holistic and comprehensive carbon accounting
makes transparent the benefits, trade-offs and shortcomings of NbS actions for climate
mitigation and sustainability outcomes. Adopting this approach is imperative for revision
of ecosystem accounting systems under the System of Environmental-Economic Accounting
and contributing to evidence-based decision-making for international conventions on
climate (UNFCCC), biodiversity (CBD) and sustainability (SDGs).
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