• Energy Research

Significance Increasing concentrations of greenhouse gases in the atmosphere are widely expected to influence global climate over the coming century. The impact on drought is uncertain because of the complexity of the processes but can be estimated using outputs from an ensemble of global models (hydrological and climate models). Using an ensemble of 35 simulations, we show a likely increase in the global severity of drought by the end of 21st century, with regional hotspots including South America and Central and Western Europe in which the frequency of drought increases by more than 20%. The main source of uncertainty in the results comes from the hydrological models, with climate models contributing to a substantial but smaller amount of uncertainty.

Significance Increasing concentrations of greenhouse gases in the atmosphere are widely expected to influence global climate over the coming century. The impact on drought is uncertain because of the complexity of the processes but can be estimated using outputs from an ensemble of global models (hydrological and climate models). Using an ensemble of 35 simulations, we show a likely increase in the global severity of drought by the end of 21st century, with regional hotspots including South America and Central and Western Europe in which the frequency of drought increases by more than 20%. The main source of uncertainty in the results comes from the hydrological models, with climate models contributing to a substantial but smaller amount of uncertainty.

Abstract Agri‐environment schemes (AES) incentivise land‐management practices aimed at mitigating environmental impacts. However, their effectiveness depends on the duration and type of management. We modelled the potential for grassland AES options in Wales (UK) to achieve positive changes in plant diversity via change in soil conditions. We modelled the response of plants and soils to the predicted effects of AES options over a 13‐year time interval. We applied scenarios of change in soil conditions in three managed grassland types, using high‐resolution baseline soil and vegetation data collected in grasslands across Wales, UK. We also applied scenarios of climate change to determine the extent to which this might modify the impact of AES intervention on plant species compositional turnover. Empirical models of soil response to extensification were constructed from published experimental data and used to drive change in soil inputs to a small ensemble of ecological niche models for British plants. These models were applied to the local pool of species in each baseline (2 × 2 m) quadrat plus a wider 10 × 10 km pool from which we draw species absent at baseline but predicted to find conditions suitable as a result of AES intervention and climate change, thus estimating dark diversity at each location. Outputs were summarised by grouping species by the ecosystem functions and services they support and by matching projected species composition to the UK National Vegetation Classification. Scenario modelling indicated that at least 10 years of management under grassland AES options were needed to achieve conditions suitable for desirable plant assemblages more typical of lower fertility habitats. Synthesis and applications: We predict that management effects will have a more marked effect on vegetation and soil than predicted climate variation up to 2029. Realising modelled changes in habitat suitability as species compositional turnover and community assembly is likely to require additional measures to assist plant dispersal and establishment.

Abstract Agri‐environment schemes (AES) incentivise land‐management practices aimed at mitigating environmental impacts. However, their effectiveness depends on the duration and type of management. We modelled the potential for grassland AES options in Wales (UK) to achieve positive changes in plant diversity via change in soil conditions. We modelled the response of plants and soils to the predicted effects of AES options over a 13‐year time interval. We applied scenarios of change in soil conditions in three managed grassland types, using high‐resolution baseline soil and vegetation data collected in grasslands across Wales, UK. We also applied scenarios of climate change to determine the extent to which this might modify the impact of AES intervention on plant species compositional turnover. Empirical models of soil response to extensification were constructed from published experimental data and used to drive change in soil inputs to a small ensemble of ecological niche models for British plants. These models were applied to the local pool of species in each baseline (2 × 2 m) quadrat plus a wider 10 × 10 km pool from which we draw species absent at baseline but predicted to find conditions suitable as a result of AES intervention and climate change, thus estimating dark diversity at each location. Outputs were summarised by grouping species by the ecosystem functions and services they support and by matching projected species composition to the UK National Vegetation Classification. Scenario modelling indicated that at least 10 years of management under grassland AES options were needed to achieve conditions suitable for desirable plant assemblages more typical of lower fertility habitats. Synthesis and applications: We predict that management effects will have a more marked effect on vegetation and soil than predicted climate variation up to 2029. Realising modelled changes in habitat suitability as species compositional turnover and community assembly is likely to require additional measures to assist plant dispersal and establishment.

The potential evapotranspiration (PET) is derived from the air temperature, specific humidity, downward long- and shortwave radiation and surface air pressure from the Climate hydrology and ecology research support system Climate hydrology and ecology research support system meteorology dataset (CHESS-met) data set (https://doi.org/10.5285/835a50df-e74f-4bfb-b593-804fd61d5eab) using a version of the Penman-Monteith equation parameterised for Food and Agriculture Organisation (FAO)-defined well-watered grass. The potential evapotranspiration with interception correction (PETI) is derived from all of the above, plus the (CHESS-met) precipitation, which is the Gridded estimates of daily and monthly areal rainfall for the United Kingdom (CEH-GEAR) precipitation (https://doi.org/10.5285/dbf13dd5-90cd-457a-a986-f2f9dd97e93c) scaled to appropriate units. The PETI calculation adds a correction for interception by a well-watered grass on rain days. Gridded potential evapotranspiration over Great Britain for the years 1961-2019 at 1 km resolution. This dataset contains two potential evapotranspiration variables calculated using the Penman-Monteith equation parameterised for well-watered short grass: daily total potential evapotranspiration (PET; kg m-2) and daily total potential evapotranspiration with interception correction (PETI; kg m-2). The data are provided in gridded netCDF files. There is one file for each variable for each month of the data set. This research has been carried out under national capability funding as part of the NERC Hydro-JULES programme (NE/S017380/1) and under the NERC Changing Water Cycle program (NE/I006087/1)

The potential evapotranspiration (PET) is derived from the air temperature, specific humidity, downward long- and shortwave radiation and surface air pressure from the Climate hydrology and ecology research support system Climate hydrology and ecology research support system meteorology dataset (CHESS-met) data set (https://doi.org/10.5285/835a50df-e74f-4bfb-b593-804fd61d5eab) using a version of the Penman-Monteith equation parameterised for Food and Agriculture Organisation (FAO)-defined well-watered grass. The potential evapotranspiration with interception correction (PETI) is derived from all of the above, plus the (CHESS-met) precipitation, which is the Gridded estimates of daily and monthly areal rainfall for the United Kingdom (CEH-GEAR) precipitation (https://doi.org/10.5285/dbf13dd5-90cd-457a-a986-f2f9dd97e93c) scaled to appropriate units. The PETI calculation adds a correction for interception by a well-watered grass on rain days. Gridded potential evapotranspiration over Great Britain for the years 1961-2019 at 1 km resolution. This dataset contains two potential evapotranspiration variables calculated using the Penman-Monteith equation parameterised for well-watered short grass: daily total potential evapotranspiration (PET; kg m-2) and daily total potential evapotranspiration with interception correction (PETI; kg m-2). The data are provided in gridded netCDF files. There is one file for each variable for each month of the data set. This research has been carried out under national capability funding as part of the NERC Hydro-JULES programme (NE/S017380/1) and under the NERC Changing Water Cycle program (NE/I006087/1)