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environment to reduce the impact of rising
temperatures. Heatwaves are often most
intense in cities, where asphalt and the dark
roofs absorb more of the sun’s rays and create
a “heat island” effect. Urban planners rarely
consider this, even in hot, wealthy places,
such as Melbourne or Abu Dhabi. But there
are simple things they could do.“We need to
design our homes better. That’s a starting
LASZLO BALOGH/REUTERS like to see more white roofs to reflect sunlight
point,”says Perkins-Kirkpatrick. She would
and better insulation and double glazing
so that, even without air conditioning, our
homes are places we can retreat to in extreme
conditions. Cities also need more shady, green
HOW TO KEEP COOL spaces to help minimise the heat island effect.
A trailblazer here is New York City, which has
taken on a massive regreening programme
in Manhattan over the past few years. The
Consuming ice pops and Remaining well hydrated There is no evidence that creation of air-conditioned public refuges
icy drinks is one of the most is crucial. However, avoid eating spicy food cools is another option that was discussed widely
effective ways to rapidly energy drinks packed with you. Choose light meals during last summer’s heatwave in Australia.
reduce body temperature. caffeine or taurine, and including lots of watery Such measures would have an added
Putting your hands and alcohol, which is diuretic fruits and vegetables, benefit. In developing countries, where
feet into icy water works and disrupts your body’s and avoid large meals power supplies are already precarious, rising
well too because they thermoregulatory system. rich in protein and fat, temperatures will inevitably lead to more
contain many capillaries which take a long time to outages – even wealthy countries struggle to
so act as radiators, digest, diverting blood to
cooling the blood. the intestines and away “Better-designed homes
In extremely hot conditions, from the skin where it
a fan does the same job can lose heat to the and greener public spaces
as a fan-assisted oven, environment.
Drinking hot beverages heating the air rather than can ease heat pressure”
sounds counter-intuitive, cooling it. But place a tub of
but heat lost through the ice behind it and it becomes meet extra demand during heatwaves, as the
sweating this induces can a makeshift air conditioner. A cold shower before authorities in South Australia were shocked
more than compensate for bed increases your body’s to discover last February. In addition, heat
the heat gained. Choose capacity to take on heat causes problems with electricity transmission
low-caffeine drinks such load in the night, helping by making cables expand and sag. Better-
as weak black tea or Avoid exercising outdoors you sleep. This is important designed homes, greener public spaces and
herbal teas, because if humidity is high. Sweat because lack of sleep communal refuges would all ease pressure
caffeine both increases will simply drip off you affects thermoregulation. on electricity grids struggling to cope during
metabolic heat and is rather than evaporating heatwaves. That, in turn, would result in lower
diuretic so dehydrates you. and cooling you down. greenhouse gas emissions.
This matters because with a temperature
rise of just 1.5 to 2°C – as agreed under the 2016
Nevertheless, our bodies are remarkably evolve to better endure extreme heat. Paris climate change deal – summer in parts
able to acclimatise – provided humidity is We already possess the raw material for of Australia will effectively become one long
low enough to allow effective sweating. evolution to work with. There is substantial heatwave by 2100. Some tropical regions
It takes about a week of exposure before the variation between people in how much they could go into a semi-permanent heatwave
thermoregulatory system starts to adjust. sweat, as well as in the number and density state, Perkins-Kirkpatrick has found. And
Then, you begin to sweat earlier and more of their sweat glands. Even so, there is little the situation will be far worse if greenhouse
profusely in response to heat, and your sweat chance we could adapt to cope with a wet gas emissions are not curbed. She foresees
composition changes, so you lose less of the bulb temperature of 35°C without hardier “devastating impacts if anthropogenic climate
sodium and potassium electrolytes that proteins able to function at a higher optimal change is not constrained as soon as possible”.
maintain blood volume. Of course, there temperature. And that would require The heat could be well and truly on. Q
are also ways to adapt behaviour to reduce significant changes to our basic biology.
overheating (see “How to keep cool”, above). Time is not on our side, but if we cannot John Pickrell is a science journalist and author based
Given enough time, humanity might even adapt our bodies, we can at least adapt our in Sydney, Australia

20 January 2018 | NewScientist | 39