Development and evaluation of an Earth-System model – HadGEM2

TL;DR: In this paper, the authors investigated the implications of the weak kinetic effect for studies of deuterium excess-humidity relationships, regional moisture recycling, and global evapotranspiration partitioning.

TL;DR: In this paper, an ensemble of climate and vegetation models is used to explore the sensitivity of Amazonian biomes to mid-Holocene climate change. But the results show that the central Amazonian rainforest biome is unaffected by mid-holocene drought.

Abstract: Author(s): Kim, JB; Monier, E; Sohngen, B; Pitts, GS; Drapek, R; McFarland, J; Ohrel, S; Cole, J | Abstract: © 2017 IOP Publishing Ltd. We analyze a set of simulations to assess the impact of climate change on global forests where MC2 dynamic global vegetation model (DGVM) was run with climate simulations from the MIT Integrated Global System Model-Community Atmosphere Model (IGSM-CAM) modeling framework. The core study relies on an ensemble of climate simulations under two emissions scenarios: a business-as-usual reference scenario (REF) analogous to the IPCC RCP8.5 scenario, and a greenhouse gas mitigation scenario, called POL3.7, which is in between the IPCC RCP2.6 and RCP4.5 scenarios, and is consistent with a 2 °C global mean warming from pre-industrial by 2100. Evaluating the outcomes of both climate change scenarios in the MC2 model shows that the carbon stocks of most forests around the world increased, with the greatest gains in tropical forest regions. Temperate forest regions are projected to see strong increases in productivity offset by carbon loss to fire. The greatest cost of mitigation in terms of effects on forest carbon stocks are projected to be borne by regions in the southern hemisphere. We compare three sources of uncertainty in climate change impacts on the world's forests: emissions scenarios, the global system climate response (i.e. climate sensitivity), and natural variability. The role of natural variability on changes in forest carbon and net primary productivity (NPP) is small, but it is substantial for impacts of wildfire. Forest productivity under the REF scenario benefits substantially from the CO2 fertilization effect and that higher warming alone does not necessarily increase global forest carbon levels. Our analysis underlines why using an ensemble of climate simulations is necessary to derive robust estimates of the benefits of greenhouse gas mitigation. It also demonstrates that constraining estimates of climate sensitivity and advancing our understanding of CO2 fertilization effects may considerably reduce the range of projections.

TL;DR: In this article, the relative importance of spatial and temporal variation of DMS fluxes to atmospheric properties as compared with the magnitude of the global total flux is assessed, and the relationship between spatio-temporal distribution of the DMS emissions and aerosol radiative effects on climate has been investigated.

TL;DR: In this paper, a hydrological forecasting model is presented that attempts to combine the important distributed effects of channel network topology and dynamic contributing areas with the advantages of simple lumped parameter basin models.

TL;DR: This work has suggested that several environmental constraints obscure the intrinsic temperature sensitivity of substrate decomposition, causing lower observed ‘apparent’ temperature sensitivity, and these constraints may, themselves, be sensitive to climate.

TL;DR: In this paper, a hydrological forecasting model is presented that combines the important distributed effects of channel network topology and dynamic contributing areas with the advantages of simple luminescence.

TL;DR: Results from a fully coupled, three-dimensional carbon–climate model are presented, indicating that carbon-cycle feedbacks could significantly accelerate climate change over the twenty-first century.