Interactions between reducing CO ₂ emissions, CO ₂ removal and solar radiation management

Abstract

We use a simple carbon cycle-climate model to investigate the interactions between a selection of idealized scenarios of mitigated carbon dioxide emissions, carbon dioxide removal (CDR) and solar radiation management (SRM). Two CO 2 emissions trajectories differ by a 15-year delay in the start of mitigation activity. SRM is modelled as a reduction in incoming solar radiation that fully compensates the radiative forcing due to changes in atmospheric CO 2 concentration. Two CDR scenarios remove 300 PgC by afforestation (added to vegetation and soil) or 1000 PgC by bioenergy with carbon capture and storage (removed from system). Our results show that delaying the start of mitigation activity could be very costly in terms of the CDR activity needed later to limit atmospheric CO 2 concentration (and corresponding global warming) to a given level. Avoiding a 15-year delay in the start of mitigation activity is more effective at reducing atmospheric CO 2 concentrations than all but the maximum type of CDR interventions. The effects of applying SRM and CDR together are additive, and this shows most clearly for atmospheric CO 2 concentration. SRM causes a significant reduction in atmospheric CO 2 concentration due to increased carbon storage by the terrestrial biosphere, especially soils. However, SRM has to be maintained for many centuries to avoid rapid increases in temperature and corresponding increases in atmospheric CO 2 concentration due to loss of carbon from the land.

Scenarios for future biodiversity loss due to multiple drivers reveal conflict between mitigating climate change and preserving biodiversity

“…Our land-use change emissions are above the estimated mean but well within the error range (Friedlingstein et al 2010). In previous work (Vaughan and Lenton 2012), a lower estimate of land-use change emissions was used for (Houghton 2008), but the absolute values agree well in 2005.…”

“…For our 'baseline' fossil fuel emissions after 2000 we follow an existing mitigation scenario (Vaughan and Lenton 2012), using estimated fossil fuel (plus cement production) emissions for al 2008), followed by a 1.7% yr −1 increase from 2005 to 2015 (the long term mean growth rate over the last 25 years), after which mitigation activity begins in earnest and it takes 40 years to transition to a 1.7% yr −1 decrease in emissions. This scenario gives peak fossil fuel emissions of 11.35 PgC y −1 in 2035, declining to 10.3 PgC y −1 in 2050.…”

The isolation and functional identification on producing cellulase ofPseudomonas mendocina

“…30 The carbon level is the important indicator of soil laborious rising, as well as a way of mitigating global warming by soil carbon sequestration. 31 Therefore, there are vital production and ecological benefit to degrade straw. It can provide a large number of high quality organic fertilizer for agriculture by straw decomposition using microorganism, It is not only beneficial to the economy, environment and society, but also provides a reasonable way of reusing the straw.…”

The Risk of Termination Shock From Solar Geoengineering

“…The idea has also informed a range of policy messages. In numerous academic papers (see, e.g., Brovkin et al, ; Clark et al, ; Pidgeon et al, ; Vaughan & Lenton, ) and high‐profile commentary pieces (Appell, ; Dean, ; Klein, ; Pierrehumbert, ; Plumer, ), it is claimed that once deployed, SRM would need to be maintained for centuries or even millennia to avoid the risk of termination shock. It has also been argued that due to the risk of termination shock, SRM should only be considered an option of last resort for emergency use (Llanillo et al, ) or that the cooling from any deployment of SRM should be limited to a level that would not cause a dangerous temperature rebound in the event of termination (Kosugi, ).…”