Thomas M. Smith et al . ("how accurate are climate simulations?", Perspectives, 19 April, p. 483) suggest that today's climate models simulate the climate history of Earth over the past 150 years "within the observed uncertainty of the observations." In comparing model results with trends in sea surface temperature in several ocean basins, they estimate the uncertainty in model output arising f...

The death toll by heatstroke in Japan, especially in Kanto region, has sharply increased since 1994 together with large interannual variability. The surface air temperature and humidity observed during boreal summers of 1980-2010 were examined to understand the role of climate in the death toll. The extremely hot days, when the daily maximum temperature exceeds 35 °C, are more strongly associat...

The role of several important factors that have played a role in Holocene climate change is examined. These forcing factors operate on different time-scales: lower frequency (millennial-scale) climate changes associated with orbital forcing, century-scale variability associated with solar forcing, and annualto decadal-scale variability associated with volcanic forcing. Feedbacks within the clim...

Understanding the contributions of aerosol properties and parameterization discrepancies to droplet number variability in a Global Climate Model R. Morales Betancourt1 and A. Nenes1,2 1School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA 2School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA Correspond...

Shifts in species' phenology in response to climate change have wide-ranging consequences for ecological systems. However, significant variability in species' responses, together with limited data, frustrates efforts to forecast the consequences of ongoing phenological changes. Herein, we use a case study of three North American plant communities to explore the implications of variability acros...

Seasonality and interannual variability in North American photosynthetic activity reflect potential patterns of climate variability. We simulate 24 yr (1983–2006) and evaluate regional and seasonal contribution to annual mean gross primary productivity (GPP) as well as its interannual variability. The highest productivity occurs in Mexico, the southeast United States and the Pacific Northwest. ...

Many aspects of human societies, such as food production, water availability and management, health, energy production and consumption etc., depend critically on climate variability and change. While some countries have the resources and infrastructure necessary to respond to the variability of climate, others are more vulnerable, to the point that large climate anomalies and extremes can cause...