Climate shock on the horizon
Weather could be unrecognisable by 2100, reports Jamie Morton
The climate in tropical regions could be unrecognisable by the end of this century if the world does nothing to slow global warming, a New Zealand scientist says.
A Kiwi author of a major study published in leading journal Nature Climate Change says New Zealand will have a “normal” climate vastly different from today’s if global emissions go unmitigated.
The study emphasises the human dimension of how unusual a warmer climate would appear to people living in different regions — particularly the billions in tropical and midlatitude parts of the planet.
The research identifies a new climate as “unfamiliar” if a year that is now normal would have occurred only once in an individual’s lifetime, or as “unknown” if it would have occurred once every few hundred years or more, on average.
“Overall, we found new climates emerge faster in inhabited areas, especially in the tropics, than in the world as a whole,” said lead author Professor Dave Frame, of Victoria University of Wellington.
“People living in tropical regions, such as the Southeast Asian nations and the Pacific Islands, are almost certain to experience ‘unfamiliar’ or even ‘ unknown’ climates by the end of this century if climate change is not slowed.”
The situation was almost as stark for many tropical African countries as well, Frame said.
“Young people alive today who are currently in the labour force in Colombia or Indonesia — if we keep on a high fossil-fuel trajectory, then, by the time they retire, they won’t recognise the climates compared with those from when they are young . . . they’ll be totally different.
“Even New Zealand will have a pretty unrecognisable climate by the end of the century if we don’t mitigate fairly strongly — but it’s our Pacific friends who really have a lot on the line here.
“Everyone talks about sealevel rise and what happens in 500 to 1000 years’ time, but actually, there’s a lot of change happening now that’s frontloaded and they are on the sharp end of it.”
The emerging effects of climate change in the coming decades could, however, be dramatically reduced.
“Unknown climates might be expected before 2050 in many tropical areas, and before the end of the century in mid-latitude areas,” said coauthor Dr Manoj Joshi of the University of East Anglia.
“However, many people alive today could reap the benefits of slowing or stopping climate change.”
Projections of 21st century climate made with significantly reduced carbon emissions show that tropical climates, especially areas with very high populations, could avoid such emergence, staying far more “familiar” to the people who live there.
Frame said cutting emissions now would do a huge amount to keep climates more familiar.
“Many of the beneficiaries of climate change mitigation include today’s young adults, people already working, paying taxes and, where institutions permit, voting.
“As this becomes understood, it has the potential to be a powerful motivating factor.”
Meanwhile, another study in the journal suggested leafy canopies might be slowing the Earth’s warming.
A team of international researchers looked at satellite images, crunched numbers and found that leaves might have slowed down warming by around one-tenth of a degree since the early 1980s.
This was mainly because of more water rising up from the soil and leaves, and changes to how air circulated.
Even NZ will have a pretty unrecognisable climate by the end of the century if we don’t mitigate fairly strongly. Professor Dave Frame