Science_Illustrated_Australia_-_Issue70_2019

32 | SCIENCE ILLUSTRATED

temperatures rise by the first one or two
degrees, because plants such as corn will
enjoy improved conditions.
However, drought and extreme weather
phenomena will likely curb the improvement
once temperatures rise even further. And the
heat will also see a series of pests spreading
towards the north in Europe, and further
south in Australia. The cane toad, for
example, is thought to be moving south into
New South Wales at approximately 3-4km
per year, based on assumptions about the
species’ environmental tolerances. But this
may be punctuated by brief periods of rela-
tively rapid movement, with the predictions
further complicated by cane toads proving
to adapt rapidly to Australian conditions.
Or consider the Colorado potato beetle,
which can destroy potato crops in huge
regions. They are rarely observed north of
Germany, and then only in small numbers,
probably because the winters are so cold that
the beetles die. But according to Chinese and
American scientists, a temperature rise of
2-3 degrees would allow the beetles to live
and breed in major parts of Scandinavia.
The heat will also pave the way for
animals that carry dangerous viruses. The

bluetongue disease, which is carried by some

midge species and affects cattle and sheep,

is already heading up through Europe, partly

because milder winters allow the midges to

spread north. That could have major conse-

quences for meat production.

But the heat is also likely to bring diseases

that could affect people. Health authorities

will hence face major new challenges that

are only exacerbated in regions where popu-

lations have multiplied in size.

Cities must protect themselves

The growing population and reduced farm-

land will force us to find new solutions when

it comes to providing food. GM crops that can

resist a harsher climate will probably be

necessary. And we must reduce our

consumption of meat markedly, as meat

production requires much more farmland.

An American study concludes that by 2050

we could save some six million square kilo-

metres of land if the people of the world all

consumed only vegetarian food.

We will also have to invest in flood

prevention. Coastal cities may need dikes and

levees that can hold back water during

severe storms and storm surges, and still

Cities grow food

Farming must be moved to rooftops and huge greenhouses in

cities – and fish will ensure a high yield with minimum effort.

FAECES FERTILISES PLANTS

1

A tank of fish supplies nutrient-rich

faeces which is diverted to the

plants. The fish could be catfish, which are

easy to keep, grow fast, and are edible.

PLANTS PURIFY THE WATER

2

The plants’ roots absorb the nutrients

in the water and grow efficiently.

The process purifies the water, which is

subsequently diverted back to the fish tank.

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(^) W
AT
ER
FOOD
Billions lack food
The UN estimates that the
Earth will need to feed more
than 11 billion people in 2100.
That could barely be
achieved with the present
climate, and in a world five
degrees warmer, with extreme
precipitation and drought, it
would be almost impossible.
The solution is to develop
much more efficient agricul-
ture than we have today.
Agriculture shift
leaves space for trees
‘Afforestation’ (creating new
forests) will be a key strategy
in the effort to remove carbon
dioxide from the atmosphere.
In order to get space for many
more trees, we must reduce
farmland. That could be done
by consuming less meat, but
we could do even more if we
moved much of our food
production to the cities.
CHALLENGE
CHALLENGE
NATURE CLIMATE