Please note that this session was withdrawn and is no longer available in the respective programme. This withdrawal might have been the result of a merge with another session.

Co-organized as CL3.04/BG3.19/ERE1.4/OS1.34
Convener: Lennart Bach | Co-conveners: Sarah Gore, Judith Hauck, David Keller

In December 2015, member states of United Nations Framework Convention on Climate Change (UNFCCC) adopted the Paris Agreement, which aims to keep the increase in the global average temperature well below 2°C. Achieving this aspirational goal requires immediate and aggressive CO2 emission reductions in the range of 1 – 5 % year-1. Unfortunately, emissions are still on the rise and the promised commitments by UNFCCC member states would at best stabilize emissions unless they are strengthened and extended. Thus, it is becoming abundantly clear that achieving the ≤2°C goal will depend on the large-scale application of “negative emission technologies (NETs)” which are supposed to remove gigatons of CO2 from the atmosphere and compensate for the delay in emission reductions.
A large variety of NETs have been proposed so far. Among these, ocean-based NETs (ONETs) gain increasing attention because their applications may require less limiting resources like freshwater, fertilizers, or space on land. Storage of atmospheric CO2 in the oceans can be realized by enhancing natural sinks (e.g. enhanced weathering, iron fertilization, artificial upwelling) or engineered isolation of CO2 with subsequent storage in the ocean or under the seafloor.
ONET operations at the gigaton scale will inevitably have major costs and logistical issues as well as legal challenges. Furthermore, their application may have harmful side-effects for the Earth System and human societies, which must be identified and evaluated before applications start.
In this session we want to bring together experts on ONETs to assess and discuss their feasibilities, costs, and side-effects. We explicitly also welcome experts working on interactions between, as well as mutual benefits of, ocean- and land-based NETs.