Heatwaves rising twice as fast in poor nations

Hot Days Frequency Index, 1960-2010.
Saturday, March 25, 2017

“The world’s poorest countries, those with the lowest greenhouse gas emissions, will be the most severely affected by extreme temperatures brought on by global warming.”

Statements such as that appear in virtually every report and article on climate change. A feature of most such statements is use of the future tense: the poorest countries will be worse-hit than the rich ones.

But new research shows that the predicted unequal climate future has actually been with us for decades. The poorest countries have already experienced twice as great a rise in extreme temperatures as rich ones — and the gap has been widening for more than 30 years.

A study published this month in the journal Environmental Research Letters, compares the number of extremely hot days and nights in high- and low-income countries, showing how the frequency has changed since the period 1961-90.

The report says: “Low income countries have experienced more than twice the increase in the number of hot days occurring each year compared to high income countries.”

The researchers point out that because most poor countries are in the tropics, the human impact of hot days is more dangerous. When normal temperatures are already “close to the upper threshold for human comfort”, even a small rise in day and night temperatures “can contribute substantially to heatwave mortality”.

The authors conclude:

  1. “Low income countries have already suffered disproportionately from global warming and have done so for decades … Low income populations should expect more severe temperature extremes earlier than high income populations as greenhouse gas emissions continue.”
  2. “If the rate of change in temperature extremes remains the same in low-income countries, then within two decades the number of hot days experienced each year will very likely triple compared to the 1961–90 average.”
     
  3. Climate change negotiations should “take into consideration the faster growth in temperature extremes that most low-income countries have already experienced due to global warming. Our findings give weight to arguments developed by many low-income countries to justify an increase in their adaptation finance as they have already experienced disproportionately adverse impacts from global warming — and are likely to continue to do so.

    “Our findings also lend support to calls for explicit loss and damage compensation.”

[Abridged from Climate and Capitalism.]

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