News concerning extreme weather events flowed in torrents during 2012 and the tide is unlikely to abate in 2013, with Australia’s bush-fire-generating heat wave, the worst winter storm in two decades in Syria and confirmation that 2012 was the hottest year ever for the US.

But it was Hurricane Sandy, which struck with deadly force over the Caribbean and north-eastern portions of the US, including New York, that emerged as last year’s poster child for such events.

Some scientists warned against directly linking the superstorm to the phenomenon of climate change. However, there is little doubt that, in the popular imagination, at least, Sandy offered a horrifying glimpse of what could be in store for citizens of a warming planet.

Another glimpse was offered in a scientific report released by the World Bank only days after the hurricane struck. Entitled ‘Turn Down the Heat: Why a 4 °C Warmer World Must Be Avoided’, the 106-page document attempts to spell out what the world could be like if it warmed by the 4 °C above preindustrial levels – a level many scientists believe is likely by 2100, unless policy action is taken.

The shocking scenarios outlined include the inundation of coastal cities; increasing risks for food production and possible higher attendant malnutrition rates; dry regions becoming dryer and wet regions wetter; unprecedented heat waves, especially in the tropics; exacerbated water scarcity in many regions; an increased frequency of high-intensity tropical cyclones; and irreversible losses of biodiversity, including coral reef systems.

The document states that no nation will be immune to the impacts, but that the distribution of impacts is likely to be tilted against many of the world’s poorest regions. For instance, the rise in the sea level is likely to be 15% to 20% higher in the tropics than the rise in the global mean, while aridity and drought are likely to increase in many developing-country regions located in tropical and subtropical areas.

The global mean temperature, the report states, is currently about 0.8 °C above preindustrial levels, while global ocean temperatures are rising, ice sheets are melting and heat waves are becoming increasingly frequent.

Underpinning the temperature rise is the increase in the concentration of carbon dioxide (CO2), which had increased from its preindustrial concentration of about 278 parts per million (ppm) to over 391 ppm in September 2012, with the rate of rise now at 1.8 ppm a year. Emissions of CO2 are currently about 35 000-million tons a year and, in the absence of policy interventions, are projected to rise to 41 000- million tons a year in 2020.

The report, along with Sandy, should serve as a reminder to a world fixated on economic stagnation, unemployment and debt that action on climate change cannot forever remain a secondary priority. As the European Commission’s climate action commissioner, Connie Hedegaard, argued recently, “weather extremes are not that extreme any more”, but rather the “new normal”.