The burden of heat-related mortality attributable to recent human-induced climate change.

Climate change affects human health; however, there have been no large-scale, systematic efforts to quantify the heat-related human health impacts that have already occurred due to climate change. Here, we use empirical data from 732 locations in 43 countries to estimate the mortality burdens associated with the additional heat exposure that has resulted from recent human-induced warming, during the period 1991-2018. Across all study countries, we find that 37.0% (range 20.5-76.3%) of warm-season heat-related deaths can be attributed to anthropogenic climate change and that increased mortality is evident on every continent. Burdens varied geographically but were of the order of dozens to hundreds of deaths per year in many locations. Our findings support the urgent need for more ambitious mitigation and adaptation strategies to minimize the public health impacts of climate change.

Persistent multi-scale fluctuations shift European hydroclimate to its millennial boundaries.

In recent years, there has been growing concern about the effect of global warming on water resources, especially at regional and continental scales. The last IPCC report on extremes states that there is medium confidence about an increase on European drought frequency during twentieth century. Here we use the Old World Drought Atlas palaeoclimatic reconstruction to show that when Europe's hydroclimate is examined under a millennial, multi-scale perspective, a significant decrease in dryness can be observed since 1920 over most of central and northern Europe. On the contrary, in the south, drying conditions have prevailed, creating an intense north-to-south dipole. In both cases, hydroclimatic conditions have shifted to, and in some regions exceeded, their millennial boundaries, remaining at these extreme levels for the longest period of the 1000-year-long record.

Use of disdrometer data to evaluate the relationship of rainfall kinetic energy and intensity (KE-I).

Determination of rainfall kinetic energy (KE) is required to calculate erosivity, the ability of rainfall to detach soil particles and initiate erosion. Disdrometers can measure rainfall KE by measuring raindrop size and velocity. In the absence of such devices, KE is usually estimated with empirical equations that derive KE from measured rainfall intensity (I). We evaluated the performance of 14 different KE-I equations to estimate the 1min KE and event total KE, and compared these results with 821 observed rainfall events recorded by an optical disdrometer in the inner Ebro Basin, NE Spain. We also evaluated two sources of bias when using such relationships: bias from use of theoretical raindrop terminal velocities instead of measured values; and bias from time aggregation (recording rainfall intensity every 5, 10, 15, 30, and 60min). Empirical relationships performed well when complete events were considered (R(2)>0.90), but performed poorly for within-event variation (1min resolution). Also, several of the KE-I equations had large systematic biases. When raindrop size is known, estimation of terminal velocities by empirical laws led to overestimates of raindrop velocity and KE. Time aggregation led to large under-estimates of KE, although linear scaling successfully corrected for this bias.

[Effects of sudden air temperature and pressure changes on mortality in the Czech Republic]. / Vliv náhlých zmen teploty a tlaku vzduchu na umrtnost v CR.

We have developed an algorithm for identifying sudden changes in air pressure and temperature over the Czech Republic. Such events were retrieved from the data covering in 1986-2005 and were matched with the daily numbers of all-cause deaths and deaths due to cardiovascular diseases from the national database, separately for the whole population and that aged 70 years and over. Excess daily mortality was determined by calculating deviations of the observed number of deaths from the expected number of deaths for each day in the respective groups. The relative deviation of the mortality the mean was calculated as the ratio of the excess mortality to the expected number of deaths. We used 3-hour air pressure data from 10 meteorological stations and hourly air temperature data from 9 stations representative of the Czech Republic. Pressure changes were evaluated on time scales of 3, 6 and 12 hours, separately for summer and winter time. Temperature changes were evaluated on a 24-hour time scale, separately for summer and winter season. Events characterized by pressure or temperature changes above the critical threshold and recorded within 24 hours at more than 50% of meteorological stations were retrieved. The critical thresholds were defined separately for each station using quantiles of distributions of air pressure and temperature changes. Relative mortality deviations for days D-2 (2 days before the change) to D+7 (7 days after the change) were averaged over the retrieved events. Statistical significance of the mean relative deviation was tested using the Monte Carlo method. Increased mortality followed large temperature increases and large pressure drops both in summer and winter months. Decreased mortality was observed after large pressure increases and large temperature drops in summer. Mortality variations are usually more pronounced in the population aged 70 years and over, and cardiovascular diseases account for most deaths after sudden temperature changes.

[High summer temperatures and mortality in the Czech Republic 1982-2000]. / Vysoké letní teploty a úmrtnost v CR v letech 1982-2000.

The heat-stress-related mortality, which is among main impacts of periods of high summer temperature on society, was reported in many European countries, but analyses focusing on central European population have been rare. Results of the analysis for the period of 1982-2000 in the Czech Republic indicate that heat stress leads to a considerably increased all-causes mortality and mortality due to cardiovascular diseases. Periods with the highest deviations of the daily number of deaths from a baseline (in all-year data) are influenza epidemics and heat waves; the distribution of days with the highest excess mortality in a year is clearly bimodal, showing a main peak in winter and a secondary one in summer. Summer days with a considerably increased mortality are almost entirely days with a positive temperature deviation from the seasonal course. Deviations of mortality from the baseline exceed 100 deaths daily (more than 30% relative increase) in heat wave peaks, and the excess total mortality during the severe 1994 heat waves was +456 deaths (+10.3%) for June 17 to 30, and 8 deaths (+12.3%) for July 24 to August 8. The relative increase in mortality due to cardiovascular diseases was even more pronounced. The mortality displacement effect played an important role, since it was estimated to account for as much as 52% of the total number of victims for the June 1994 heat wave and 48% for the July-August heat wave. People who would die soon without oppressive weather conditions make about half of the total number of deaths, which is a larger value compared to what other studies reported. The increased mortality is observed at maximum (average, minimum) daily temperatures higher than 25 degrees C (18 degrees C, 14 degrees C) and their anomalies from mean seasonal courses larger than 3 degrees C. The same values hold for both the total and cardiovascular mortality. The mortality response at high temperatures is more pronounced in females than males. Correlations between mortality and temperature variables (including heat index) are positive and statistically significant (P = 0.01), stronger for deviations of meteorological variables from seasonal courses than for raw values, in females than males, and for heat index than for any temperature variable and summer simmer index. The unlagged correlations are stronger than correlations with lags 1-3 days; positive values of correlation coefficients hold for lags 0 to 3 days only while at lags of 4 to 25 days, the link is negative (mostly statistically significant) which demonstrates the mortality displacement effect and its time extent.