jun
Emit now, mitigate later? Simulating the Earth system response to zero and negative emissions
Välkommen till detta seminarium med Jörg Schwinger, forskare vid NORCE och Bjerknes Centre for Climate Research. Observera att seminariet ges på engelska.
Abstract
We have simulated a large set of idealized simulations with the Norwegian Earth System Model (NorESM2) to explore the Earth system response to net-zero and net-negative CO2 emissions. Our simulations reach net-zero emissions after different levels of prior emissions and are complemented by phases of negative emissions such that we obtain scenarios of temperature overshoots of different magnitude and duration. We will present results from these simulations focusing on two aspects.
First, we show that in our model, which has a strong AMOC decline in response to global warming, high northern latitudes cool substantially relative to peak warming after emissions are phased out. Interestingly, such cooling can be amplified under deliberate CO2 removal (CDR) and results in a temporary undershoot of a targeted temperature level, depending on the timing of CDR relative to the recovery of AMOC. We present evidence that such behavior might be generally found in Earth system models that show a strong AMOC decline in response to anthropogenic forcing.
Second, we investigate the centennial scale reversibility of the Earth system after an overshoot. In our model, increased carbon loss from land during an overshoot is compensated by increased ocean uptake such that atmospheric CO2 concentrations are remarkably similar in the overshoot simulations compared to the reference simulation without overshoot. We find that some aspects of the Earth system (e.g., surface temperature, surface pH) are indeed reversible except under very large overshoots, which are unfeasible in view of limited CDR capacity. In line with previous studies, we find irreversibility for permafrost carbon loss and deep ocean properties.
Om Jörg Schwinger
Jörg är senior forskare vid NORCE och Bjerknes Centre for Climate Research i Norge. Han disputerade i geofysik vid universitetet i Köln, Tyskland. Efter att ha flyttat till Bergen i Norge har han arbetat vid Bjerknes Centre for Climate Research med modellering av den globala kolcykeln (och andra biogeofysiska cykler) och deras relation till det globala klimatet.
Med hjälp av jordsystemmodeller har han arbetat med att kvantifiera dagens kolflöden i havet, återkopplingar i kolcykeln och framtida prognoser. Hans senaste forskningsinriktning är kolcykelns och jordsystemets reaktion på nettonoll- och nettonegativa utsläpp.
Om evenemanget
Plats:
Sal "Atmosfären", Geocentrum II (2 vån), Sölvegatan 12, Lund
Kontakt:
lars [dot] nieradzik [at] nateko [dot] lu [dot] se