carbon cycle fundamentals, the role of negative emissions

Pep CanadellCSIRO, Global Carbon Project

Canberra

Carbon Cycle Fundamentals, the Role of Negative Emissions & simulating

their response

andrew.lenton@csiro.au

Andrew LentonCSIRO Oceans and Atmosphere

Where are we & the growing need for Neg

Emissions

Present Day Anthropogenic Perturbation

Keller Lenton et al, Current Climate Change Reports 2018

Current Emissions & Paris

Decarbonization Rates

Peters et al. 2013, NatureCC; Global Carbon Budget 2016Global Carbon Project 2017; Mitigation curves after Raupach et al. 2014, NatureCC

Negative Emissions or Carbon Dioxide Removal

• The removal of carbon dioxide from the atmosphere• CDR: Carbon Dioxide Removal • Not avoided emissions

Afforestation/Reforestation Direct CO2 RemovalBiofuels with CCS

Canadell & Schulze 2014, NatCom

Negative Emissions Technologies

Not all sectors can be easierly decarbonised(> 1/3 total GHGs)

Non-CO2 EmissionsCO2 Emissions CO2 Emissions

Already counting on these:

Neg Emissions have long been of our low emissions pathways (IPCC)

Bioenergy Carbon Capture and Storage (BECCS)

Increasingly reliant on Neg Emissions - emissions on credit.

Can’t get to Paris without NE.Anderson & Peters, 2016

How will the earth system (carbon cycle)

respond to Negative Emissions?

Reducing Emissions to limit warmingNet Positive Emissions with CDR

Net Negative Emissions with CDR

Anderson & Peters, 2016

Net Positive Emissions

Carbon cycle response to CDR

Net positive emissions with CDR Net negative emission

Natural sinks weaken Sinks become sources of CO2

These feedbacks are not well quantified !

Carbon Cycle Feedbacks Oppose CDR!

Keller Lenton et al, Current Climate Change Reports 2018

Modelling the Earth System Response to Negative Emissions

An initiative that brings together a suite of Earth System Models (ESMs) and Earth System Models of Intermediate Complexity (EMICs) in a common framework to investigate Carbon Dioxide Removal (CDR) or Negative Emissions

Modelling the Earth System Response to Negative Emissions

CDR Efficiency: Direct Air Capture

Difference between GROSS and NET CDR

Earth System Reversibility

Other methods

Need to get Serious….

• <1980s – Nuclear

•1990s – Carbon Capture and Storage

•2000s – Bioenergy

•2010s – Bioenergy + Carbon Capture and Storage = BECCS

•2020s – Direct CO2 Removal

The GREAT Climate Solutions

Foresighting & Modelling

Lenton, Boyd et al, NCC 2019Science, Social License & Governance

Emmerson, in prep

Earth System Reversibility

Lenton et al, 2017