Within the next 20 to 60 years, the coolest days of summer will be hotter than the scorchers of today. That's the grim forecast from a forthcoming paper in Climatic Change Letters by Noah Diffenbaugh of Stanford University's Woods Institute for the Environment and research assistant Michael Scherer. Their analysis of more than 50 climate models led them to conclude that many parts of the earth face "the permanent emergence of unprecedented summer heat."
According to our projections, large areas of the globe are likely to warm up so quickly that, by the middle of this century, even the coolest summers will be hotter than the hottest summers of the past 50 years.
More worrisome still is the fact that their analysis was based on a "relatively modest forecast of greenhouse gas emissions in the 21st century." Actual increases could be far higher. For example, according to a study in Tellus by NOAA and the National Snow and Ice Data Center, melting in the arctic regions could release vast amounts of carbon currently frozen in permafrost, vastly increasing planetary greenhouse gases. --Paul Rauber