The need for and limits to negative emissions Sabine Fuss & Pete Smith On behalf of 30+ collaborators from many institutes and GCP Mercator Research Institute on Global Commons and Climate Change, Berlin & Institute of Biological & Environmental Sciences, University of Aberdeen Our Common Future under Climate Change Conference, July 7-10 2015, Paris
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The need for and limits to
negative emissions
Sabine Fuss & Pete Smith On behalf of 30+ collaborators from many institutes and GCP
Mercator Research Institute on Global Commons and Climate Change, Berlin
&
Institute of Biological & Environmental Sciences, University of Aberdeen
Our Common Future under Climate Change Conference, July 7-10 2015, Paris
The need for negative emissions
• IPCC AR5: Achieving 2C is
still possible, but it entails
huge contributions from
bioenergy - in most scenarios
combined with Carbon
Capture & Storage to go
“negative“.
• BECCS need 2-10 Gt
CO2/yr in 2050 5–25% of
2010 CO2 emissions
• Current global mean removal
of CO2 by ocean and land
sinks is 9.2 ± 1.8 Gt CO2 and
10.3 ± 2.9 Gt CO2, resp.
2
Data: CDIAC/GCP/IPCC/Fuss et al 2014
The need for negative emissions cont’d
3
Based on Figure TS.17, IPCC, WG3, AR5, 2014.
How can we go (net) negative?
The technology most widely used in climate stabilization
scenarios of AR5 is Bioenergy combined with CCS (BECCS).
4
Source: Applied Energy Handbook, Wiley.
Other negative emissions options:
• Afforestation (also in AR5, see next slide)
• Increases in soil carbon storage (biochar…)
• Direct air capture (coming up)
• Enhanced weathering (coming up)
Land-use and management changes:
• Saturation of CO2 removal over time
• Sequestration reversible (terrestrial carbon stocks inherently vulnerable to disturbance)
Geo-engineering options:
• Quicker and cheaper to ramp up
• Embody a much larger scale of mostly unknown risks
• Not able to deal with other consequences of increased CO2 concentrations such as ocean acidification
• Afforestation – albedo, water, competition for land
• BE/BECCS – water, competition for land Smith et al. (2015)
Conclusions
• Negative emissions of 3.6 GtC-eq./yr in 2100 are possible with BECCS and DAC
• EW and AR can provide less negative emissions than this in 2100
• All NETs have limits / downsides and none is a magic bullet
• Need more R&D and pilot projects – then to see if technology is scalable Most probably will need to look into other NETs to complement BECCS and AR, e.g. DAC, EW
• Improve governance to ensure sustainable implementation of NETs
• Safe storage needed, in addition to storage from fossil CCS.
• An over-reliance on NETs in the future, if used as a means to allow continued use of fossil fuels in the present, is extremely risky since our ability to stabilise the climate at <2C declines as cumulative emissions increase (Kriegler et al., 2014, Luderer et al., 2012)
• A failure of NETs to deliver expected mitigation in the future, due to any combination of biophysical and economic limits examined here, leaves us with no “Plan B”
• “Plan A” must be to reduce GHG emissions aggressively now
Smith et al. (2015)
Contact
Please also visit http://www.cger.nies.go.jp/gcp/magnet to learn more about GCP‘s research initiative „Managing Global Negative Emissions Technologies“