By far the most disturbing study led by the University of Hawaii argued that the pattern of escalating intensity and frequency indicates that anthropogenic climate change is rapidly pushing the climate system into a ‘new normal’, that breaks fundamentally with the preceding 150 years. The paper came up with the concept of “climate departure” to explain its prediction that in coming decades, the trajectory of escalating extreme weather signals that the climate is destined to ‘depart’ from the historical norm of weather as we have known it. On a business-as-usual trajectory, the initial locus of this “climate departure” will occur within the next decade in the tropics—that is, a vast region encompassing parts of the Middle East, Central Asia, South Asia and Africa. On a global scale, “climate departure”—the entry into a ‘new normal’ of extreme weather—will hit around 2047. Even under stringent carbon emission mitigation scenarios, this tendency to “climate departure” will not be halted—only postponed a few more decades, to around 2069 (Mora et al. 2013).
While the oceans are dying, above the oceans the atmosphere is already experiencing the direct impact of climate change in the form of intensifying heatwaves and extreme weather events. The increasing frequency—and increasing intensity—of heat waves is perhaps one of the most overt manifestations of the dangerous impacts of climate change. Since 1950, the number of heat waves worldwide has increased, heat waves have become longer, and the hottest days and nights are hotter than ever before. In recent years, the global area affected by summer heatwaves has increased 50-fold. Within the US, the direct impact of more frequent and intense heatwaves is an increasing frequency and duration in wildfires (Trendberth et al. 2012).