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WHY DENY
?
From the beginning of human existence we have pondered the great mysteries of our world, and
scientists have often been at the forefront of this quest for answers. While the average person may not
always understand the details behind certain scientific principles, we tend to trust that they are correct.
We may not know the equations behind it, but if an apple falls on our head we are happy to call that
“gravity”.
This trust, however, has not been so readily applied when it comes to the science of climate change.
But why? Hereʼs a closer look at three common reasons for climate change skepticism and some
points that may help turn denial into acceptance.
I don’t understand
Global warming Global warming refers to the trend observed over the past century that land, air and
ocean temperatures are increasing. In other words, our planet is getting warmer and warmer.
Why? When the sunʼs energy passes through our
atmosphere it reaches the earthʼs surface and is partly
absorbed and partly reflected back towards the
“I want to believe,
atmosphere as heat. Gases in the earthʼs atmosphere
but I don’t have the
help to stop that heat from radiating out into space.
facts”
This insulating effect means that the earth is warm and
habitable. However, too much of these gases (known as
greenhouse gases) in the atmosphere leads to an amplification of this natural
warming effect. This is what we are currently experiencing - having too many greenhouse gases in our
atmosphere has meant that more and more heat is being trapped, causing global warming.
Greenhouse gases Greenhouse gases include carbon dioxide (CO2), methane (CH4), nitrous oxide
(N2O), ozone (O3), chlorofluorocarbons (CFCs) and hydrofluorocarbons (HFCs). These greenhouse
gases are all directly influenced by human activity. CO2 is the most famous of the greenhouse gases,
because it is one of the biggest contributors to the warming of our planet. It is also one of the gases
most obviously linked to human behaviour,
particularly the burning of fossil fuels.
Ten Signs of Global Warming
Air temperature
How can you tell that the planet is warming?
Scientists measure temperature (land, sea and
Humidity
Snow cover
air), rainfall, sea level and a variety of other climate
indicators and analyse the data collected over
Temperature over oceans
time. This analysis allows scientists to identify
trends and predict future outcomes. Models of
Glaciers
these predictions are cross-checked against new
Sea level
data in order to show whether the predicted
Sea surface temperature
outcomes are likely to come true. Measurements
Temperature over land
have shown that the earth is indeed warming, and
Sea ice
so far models that have predicted further increases
Ocean heat content
in temperature, sea level rise, and other similar
Yellow indicators would be expected to increase in a warming world and are, in
indicators have been confirmed to be accurate fact, increasing. Purple indicators would be expected to decrease in a warming
world and are, in fact, decreasing. Diagram adapted from NAOO.
global warming is continuing.
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It’s not our fault
Not all deniers believe that climate change is not happening. Some deniers recognise that the world is
warming, but argue that human activity is not the cause of the warming. In fact there is clear empirical
evidence to connect the rise of CO2 emissions from human activity with the rise of CO2 in the
atmosphere and with the subsequent warming impacts.
Measuring CO2 Levels For decades, climatologists
have been taking measurements of the levels of
“I don’t deny climate
CO2 in the atmosphere. Scientists can also collect
change, I just don’t
data about atmospheric conditions in previous
think humans have
centuries by analysing air trapped in ice that was
caused it””
formed long ago. This gives a clear picture of the
changing levels of CO2 in the atmosphere over the
past century. There is a sharp rise in atmospheric CO2
directly correlating to the increased
CO2 emissions produced by humans as a result of burning f o s s i l f u e l s s i n c e t h e I n d u s t r i a l
Revolution. Therefore, by simply looking at the amount of CO2 emissions produced by humans over
time alongside the atmospheric CO2 levels over time we can see a direct link between human activity
and an increase in greenhouse gas in the
Ten Signs of Human Fingerprint on Climate Change atmosphere.
Cooling stratosphere
Less heat
escaping
to space
Rising tropopause
More fossil fuel carbon in the air
Shrinking thermosphere
Less oxygen in the air
More heat returning to earth
30 billion tonnes of CO2 per year
More fossil fuel carbon in coral
Nights warming faster than days
Image: www.skepticalscience.com.
Visit the website to read more detailed descriptions of the the terms used above.
What does this mean? Increased CO2 levels
leads to various impacts such as those discussed
in the previous section. However, there are certain
impacts that can be directly attributed to an
increase of CO2 from human activity as opposed to
other natural factors that might lead to warming.
Because increased greenhouse gases mean that
heat is trapped by the lower atmosphere and
radiated back towards the surface of the earth, the
upper atmosphere remains cool. If, on the other
hand, global warming was caused by solar activity
it would mean that the upper atmosphere would
also be warm. This is not the case. Other
observations (see diagram) also demonstrate that
warming is being caused by greenhouse gases
emitted by humans, not by other sources.
I’d rather not think about it
Perhaps at the heart of most forms of denial is the simple fact that climate change is the kind of issue
that we would rather not have to think about. But if we deny out of fear, and fail to act, it will only mean
that our greatest fears are more likely to come true. The more you learn the facts of climate change,
the more empowered you will become. We can each be a part of the solution to climate change, but
first we must leave denial behind.
Continue learning more by reading the latest CSIRO publication Climate Change:
Science and Solutions for Australia (available online). The website Skeptical
Science (www.skepticalscience.com) is also a fantastic resource
for organised science-focused rebuttals of common denier
arguments. They also have a mobile phone app so that you
“It’s all too scary
can always have the facts at your fingertips.
and depressing!””
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Why Deny? has been produced by the Social
Justice Committee of CLRI(NSW) www.clrinsw.org