6 research outputs found
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Projected impacts on heat-related mortality from changes in the mean and variability of temperature with climate change
The aim of this paper is to demonstrate the importance of changing temperature variability
with climate change in assessments of future heat-related mortality. Previous studies have only considered
changes in the mean temperature. Here we present estimates of heat-related mortality resulting from climate
change for six cities: Boston, Budapest, Dallas, Lisbon, London and Sydney. They are based on climate
change scenarios for the 2080s (2070-2099) and the temperature-mortality (t-m) models constructed and
validated in Gosling et al. (2007). We propose a novel methodology for assessing the impacts of climate
change on heat-related mortality that considers both changes in the mean and variability of the temperature
distribution
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Climate change and heat-related mortality in six cities Part 2: climate model evaluation and projected impacts from changes in the mean and variability of temperature with climate change
Previous assessments of the impacts of climate
change on heat-related mortality use the "delta method" to
create temperature projection time series that are applied to
temperature-mortality models to estimate future mortality
impacts. The delta method means that climate model bias in
the modelled present does not influence the temperature
projection time series and impacts. However, the delta
method assumes that climate change will result only in a
change in the mean temperature but there is evidence that
there will also be changes in the variability of temperature
with climate change. The aim of this paper is to demonstrate
the importance of considering changes in temperature
variability with climate change in impacts assessments of
future heat-related mortality. We investigate future heatrelated
mortality impacts in six cities (Boston, Budapest,
Dallas, Lisbon, London and Sydney) by applying temperature
projections from the UK Meteorological Office
HadCM3 climate model to the temperature-mortality models
constructed and validated in Part 1. We investigate the
impacts for four cases based on various combinations of
mean and variability changes in temperature with climate
change. The results demonstrate that higher mortality is
attributed to increases in the mean and variability of temperature
with climate change rather than with the change in
mean temperature alone. This has implications for interpreting
existing impacts estimates that have used the delta
method. We present a novel method for the creation of
temperature projection time series that includes changes in
the mean and variability of temperature with climate change
and is not influenced by climate model bias in the modelled
present. The method should be useful for future impacts
assessments. Few studies consider the implications that the
limitations of the climate model may have on the heatrelated
mortality impacts. Here, we demonstrate the
importance of considering this by conducting an evaluation
of the daily and extreme temperatures from HadCM3,
which demonstrates that the estimates of future heat-related
mortality for Dallas and Lisbon may be overestimated due
to positive climate model bias. Likewise, estimates for
Boston and London may be underestimated due to negative
climate model bias. Finally, we briefly consider uncertainties
in the impacts associated with greenhouse gas
emissions and acclimatisation. The uncertainties in the
mortality impacts due to different emissions scenarios of
greenhouse gases in the future varied considerably by
location. Allowing for acclimatisation to an extra 2°C in
mean temperatures reduced future heat-related mortality by
approximately half that of no acclimatisation in each city
No saturation in the accumulation of alien species worldwide
Although research on human-mediated exchanges of species has substantially intensified during the last centuries, we know surprisingly little about temporal dynamics of alien species accumulations across regions and taxa. Using a novel database of 45,813 first records of 16,926 established alien species, we show that the annual rate of first records worldwide has increased during the last 200 years, with 37% of all first records reported most recently (1970–2014). Inter-continental and inter-taxonomic variation can be largely attributed to the diaspora of European settlers in the nineteenth century and to the acceleration in trade in the twentieth century. For all taxonomic groups, the increase in numbers of alien species does not show any sign of saturation and most taxa even show increases in the rate of first records over time. This highlights that past efforts to mitigate invasions have not been effective enough to keep up with increasing globalization.© The Author(s) 201