Historically unprecedented climates to arrive by mid-century

Muzaffar Bukhari

If there was one overarching point that the fifth Intergovernmental Panel on Climate Change report took pains to stress, it was that the degree of change in the global climate system since the mid-1950s is unusual in scope. Depending on what exactly you measure, the planet hasn't seen conditions like these for decades to millennia. But that conclusion leaves us with a question: when exactly can we expect the climate to look radically new, with features that have no historical precedent?

The answer, according to a modeling study published in this week's issue of Nature, is "very soon"—as soon as 2047 under a "business-as-usual" emission scenario and only 22 years later under a reduced emissions scenario. Tropical countries will likely be the first to enter this new age of climatic erraticness and could experience extreme temperatures monthly after 2050. This, the authors argue, underscores the need for robust efforts targeted not only at protecting those vulnerable countries but also the rich biodiversity that they harbor.

Developing an index, one model at a time

Before attempting to peer into the future, the authors, led by the University of Hawaii's Camilo Mora, first had to ensure that they could accurately replicate the recent past. To do so, they pooled together the predictive capabilities of 39 different models, using near-surface air temperature as their indicator of choice.