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We assess climate impacts of global warming using ongoing observations and paleoclimate data. We use Earth’s measured energy imbalance, paleoclimate data, and simple representations of the global carbon cycle and temperature to define emission reductions needed to stabilize climate and avoid potentially disastrous impacts on today’s young people, future generations, and nature. A cumulative industrial-era limit of ∼500 GtC fossil fuel emissions and 100 GtC storage in the biosphere and soil would keep climate close to the Holocene range to which humanity and other species are adapted. Cumulative emissions of ∼1000 GtC, sometimes associated with 2°C global warming, would spur “slow” feedbacks and eventual warming of 3–4°C with disastrous consequences. Rapid emissions reduction is required to restore Earth’s energy balance and avoid ocean heat uptake that would practically guarantee irreversible effects. Continuation of high fossil fuel emissions, given current knowledge of the consequences, would be an act of extraordinary witting intergenerational injustice. Responsible policymaking requires a rising price on carbon emissions that would preclude emissions from most remaining coal and unconventional fossil fuels and phase down emissions from conventional fossil fuels., PLoS ONE, 8 (12), ISSN:1932-6203

We assess climate impacts of global warming using ongoing observations and paleoclimate data. We use Earth’s measured energy imbalance, paleoclimate data, and simple representations of the global carbon cycle and temperature to define emission reductions needed to stabilize climate and avoid potentially disastrous impacts on today’s young people, future generations, and nature. A cumulative industrial-era limit of ~500 GtC fossil fuel emissions and 100 GtC storage in the biosphere and soil would keep climate close to the Holocene range to which humanity and other species are adapted. Cumulative emissions of ~1000 GtC, sometimes associated with 2°C global warming, would spur “slow” feedbacks and eventual warming of 3–4°C with disastrous consequences. Rapid emissions reduction is required to restore Earth’s energy balance and avoid ocean heat uptake that would practically guarantee irreversible effects. Continuation of high fossil fuel emissions, given current knowledge of the consequences, would be an act of extraordinary witting intergenerational injustice. Responsible policymaking requires a rising price on carbon emissions that would preclude emissions from most remaining coal and unconventional fossil fuels and phase down emissions from conventional fossil fuels.

For published content see: DOI: 10.1111/gcbb.12565 Land use change is a major driver of species loss worldwide, the extent and intensity of agricultural land use poses particular pressures for biodiversity and the ecosystem services it provides. In recent years, agroecosystems have seen the introduction of 2nd generation bioenergy crops in order to tackle anthropogenic climate change, providing a renewable alternative to fossil fuels. In this thesis I study the impact of cultivating two commercial perennial energy crops (PECs), Miscanthus x giganteus and willow short-rotation coppice, when compared to the cereal crops they replace. I investigate processes relevant to the provisioning of pollination and decomposition services and explore patterns of soil element bioaccessibility alongside analyses of the similarity and diversity of soil bacterial communities. When compared to cereals, I find a consistent increase in pollinator (hoverfly, bumblebee and butterfly/moth) wildflower visitation in the margins of willow but not Miscanthus. In Miscanthus, opposing trends arose for different pollinator taxa: butterflies/moths were more frequent flower visitors in Miscanthus margins than cereal margins, while hoverfly flower visits were most frequent in cereal margins. Furthermore, the availability of margin wildflowers was enhanced in willow but not Miscanthus and the seed set of margin phytometers was similar between Miscanthus and cereals. Cultivation of willow, in particular, may therefore yield local conservation benefits for both wildflowers and pollinators. However, there was no evidence for enhancement of pollinator activity in cereals adjacent to either PEC, indicating that the strategic cultivation of these crops is unlikely to enhance pollinator service provision in the wider agri-environment. For investigated soil elements, bioaccessibility in PECs did not differ significantly to cereal controls, and denaturing gradient gel electrophoresis (DGGE) revealed no difference in the diversity of bacterial communities. Similarly, DGGE fingerprint patterns did not indicate the development of crop specific assemblages, demonstrating that the mobility of soil elements and structure of bacterial communities were principally determined by factors other than the identity of the crop cultivated. Investigation of meso-microfaunal decomposition rates in Miscanthus using litter bags demonstrated an impact on decomposition processes, with a significant increase in winter decomposition rates in the PEC when compared to cereals.