Increase of extreme events in a warming world

Abstract

We develop a theoretical approach to quantify the effect of long-term trends on the expected number of extremes in generic time series, using analytical solutions and Monte Carlo simulations. We apply our method to study the effect of warming trends on heat records. We find that the number of record-breaking events increases approximately in proportion to the ratio of warming trend to short-term standard deviation. Short-term variability thus decreases the number of heat extremes, whereas a climatic warming increases it. For extremes exceeding a predefined threshold, the dependence on the warming trend is highly nonlinear. We further find that the sum of warm plus cold extremes increases with any climate change, whether warming or cooling. We estimate that climatic warming has increased the number of new global-mean temperature records expected in the last decade from 0.1 to 2.8. For July temperature in Moscow, we estimate that the local warming trend has increased the number of records expected in the past decade fivefold, which implies an approximate 80% probability that the 2010 July heat record would not have occurred without climate warming.

Understanding the rapid summer warming and changes in temperature extremes since the mid-1990s over Western Europe

“…In the last few decades, Europe has warmed not only faster than the global average, but also faster than expected from anthropogenic greenhouse gas increases (Ruckstuhl et al 2008;Philipona et al 2009;van Oldenborgh et al 2009). With the warming, Europe experienced record-breaking heat waves and extreme temperatures that imposed disastrous impacts on individuals, and society (Stott et al 2004;Fischer and Schär 2010;Barriopedro et al 2011;Christidis et al 2011Christidis et al , 2012Hegerl et al 2011;Rahmstorf and Coumou 2011;Hoerling et al 2012;Schubert et al Abstract Analysis of observations indicates that there was a rapid increase in summer (June-August) mean surface air temperature (SAT) since the mid-1990s over Western Europe. Accompanying this rapid warming are significant increases in summer mean daily maximum temperature, daily minimum temperature, annual hottest day temperature and warmest night temperature, and an increase in frequency of summer days and tropical nights, while the change in the diurnal temperature range (DTR) is small.…”

Quasiresonant amplification of planetary waves and recent Northern Hemisphere weather extremes

“…Schär and colleagues (2004) (3) proposed that the observed climatic warming trend (i) shifted the probability distribution of summer temperatures toward warmer values and (ii) widened this probability distribution so that extreme values become much more likely, possibly as the result of a positive feedback between temperature and soil dryness. We note that a shift and widening of the probability distribution due to global warming almost certainly will lead to a marked increase in the frequency of extreme warmseason events (5)(6)(7). However, even when the warming trend found in the data is fully taken into account, and if an increase in SD of 50% is assumed, the extreme temperatures and duration of the summer 2003 heat wave still would be highly unlikely.…”

Hot temperatures can force delayed mosquito outbreaks via sequential changes in Aedes aegypti demographic parameters in autocorrelated environments

“…Ultimately, this entomological research could provide a basis to test the existence of sequential changes in life history traits with the advent of "hot" environments, a phenomenon that is becoming increasingly more frequent worldwide (Hansen et al 2012;Rahmstorf & Coumou 2011). From the modeling perspective, analytical results for population growth in autocorrelated environments (Tuljapurkar 1982) need to be extended to non-linear (density-dependent) cases or generalized for non-Markovian situations (where memory goes beyond the previous time step in discrete time models).…”