everything you wanted to know about
climate change but were too afraid to ask.
WORDSLUKE RYANILLUSTRATIONSBECI ORPINheavyweather
So, what actually is global warming? The Earth's atmosphere
is a miraculous thing. A semi-permeable layer of gas that
stretches almost 500 kilometres into space, the atmosphere does
an excellent job of keeping harmful solar radiation out, while
trapping life-giving heat and water in. It's mostly made up of
oxygen, nitrogen and argon – aka the air we breathe – but also
contains trace amounts of carbon dioxide, methane and ozone
(a naturally occurring molecule comprised of three oxygen atoms).
These latter molecules are known as ‘greenhouse gases’ for their
ability to absorb and transmit heat, much like a garden greenhouse.
Despite only making up around one-tenth of one per cent of the
atmosphere, these greenhouse gases have a whopping big effect
on what happens to the planet below. Without them, the average
temperature on the surface of the Earth would be about -18°C,
as opposed to the 15°C we enjoy today. When we talk about global
warming, we're referring to what happens when the concentration
of greenhouse gas in the atmosphere increases. The more carbon
dioxide, methane and ozone there is in the atmosphere – these
gases are created when we burn fossil fuels like coal and oil –
the better the atmosphere becomes at trapping in heat. The result:
an Earth where the average temperature is rapidly rising.
............... ....
Why is that bad? Over the course of its 4.5-billion-year history,
the Earth has spent most of its time in one of two distinct states:
icehouse and greenhouse. Whenever the state switches, it
prompts devastating climate change and mass extinction events.
For the past 34 million years, the Earth has been in an icehouse
state. Almost every species of plant and animal alive today has
evolved within the wet, moist, cooler climate conditions of an
icehouse Earth. Glaciers, rainforest, tundra – we like it that way.
But we might not have our way for much longer. Geological research
has shown that the transition from icehouse to greenhouse is driven
by the increasing concentration of carbon dioxide in the atmosphere- a process that typically takes tens of millions of years to see
through. Humans, on the other hand, have had heavy industry for
a little over 200 years, and in that time have already had a
geologically significant effect on the levels of carbon dioxide in
our atmosphere. At a time when we should be gently sliding into
another Ice Age, we are, instead, in danger of causing a full-blown
greenhouse transition.
...................Couldn't this be caused by natural processes? In a word, no.
While all the Earth's previous transitions have been associated with
natural events and trends – the Late Devonian extinction that took
place about 360 million years ago was literally caused by an excess
of trees – these have also all occurred over tens of thousands,
if not millions of years. The speed of the increase in carbon dioxide
we're witnessing right now is almost unprecedented, from 280 parts
per million at the beginning of the Industrial Revolution in the late
1700s, to 410 parts per million in 2018, the highest level in some
20 million years. We are basically a mega-volcano and the asteroid
fromArmageddon rolled into one....................What's the difference between global warming and climate
change?You’ve probably heard the two terms being thrown about,
and they’re essentially referring to the same thing, although global
warming is generally understood as the phenomenon that causeslearn something new