A global shift towards a plant-based diet could halve the land and water used for agriculture – and halve the carbon emissions – but politicians fear angering voters by recommending a dietary shift.įacing all this gloom means we need imagineers as well as climatologists. While immediate harm to people grabs the headlines, what’s even more destructive could be the impact of heat and humidity on food production for an expanding population. But tell that to New Yorkers choking on wildfire smoke, or people in Phoenix trapped under that heat dome. Should holidaymakers avoid buying homes in Greece? China is vulnerable to extremes – how should its economy adapt? The US has considered itself less vulnerable. ![]() But, as India starts stockpiling rice with a temperature rise of 1.2C, what useful advice can scientists offer for a 3C world? Just how bad will things be by then? That number positively frightens many climate scientists. We would be lucky to get away with 2.5C, he said. Watson said at current rates the world would almost certainly exceed the agreed maximum temperature rise of 1.5-2C. But tell that to people in Phoenix trapped under that heat dome.’ Photograph: Matt York/AP ‘The US has considered itself less vulnerable. Prof Jane Francis, director of the British Antarctic Survey, told me a few months ago the latest science on ice melt was “truly scary”. He added: “Scientists are only now starting to understand the response of large ice sheets in Greenland and Antarctica – and it is very disturbing.” We probably underestimated the consequences.” But they are more severe than we predicted 20 years ago, and more severe than the predictions of five years ago. None of the observed changes so far (with a 1.2C temperature rise) are surprising. ![]() The former IPCC chief, Prof Bob Watson, told me: “I am very concerned. The macro models also failed to project the effect of current elevated temperatures on ice at both poles. ![]() Unfortunately, good information on precipitation is proving a bit tricky to find. Good information about the future of monsoon rain would be a godsend for farmers who rely upon it – not just in India but in southern China. ![]() Major uncertainties remain, too, over rainfall. In the 35 years I covered the environment for the BBC, I recall speculation that the warmth could stay deep for decades, perhaps centuries – not that some of it would suddenly burst up to the surface off the coast of northern Britain. The models also couldn’t warn us accurately about the emergence of the heat trapped deep in the ocean, which soaks up 90% of the world’s excess warmth. This periodic report inevitably lags behind new science and – under pressure from some governments and industries, as well as a desire not to scaremonger – its pronouncements tend to be conservative. I can’t find heat domes mentioned in the bible of climate change, the IPCC report. Yet the panel couldn’t warn us about the appalling heat dome that’s been searing North America. So, for instance, we’ve already had a global temperature rise of about 1.2C: that’s in line with IPCC projections. The influential Intergovernmental Panel on Climate Change (IPCC) says cranking up global temperature by half a degree will bring much more extreme weather, and it can be more often, more intense, or extended in duration – but exactly how much more, it can’t precisely say. But lately, leading researchers have made a painful confession: even their most sophisticated models can’t yet foresee exactly how Earth systems will respond to those higher temperatures.
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