The Threat Posed by Climate Change

The Myths against Climate Change Resources to download

It is now widely accepted that human-induced climate change poses a significant threat to the welfare of the international community and the natural environment. Between the mid 19th century and the early 21st century, the global average surface temperature increased from around 13.7ºC (degrees centigrade) to 14.5ºC. The rate of warming has doubled over the past 50 years.

If the international community does not make a concerned effort to reduce greenhouse gas emissions, there is a risk that the global average surface temperature could rise by a further 6ºC by the end of this century.

Why is the world warming?

It is believed that most of the observed warming since the mid-20th century has been driven by the accumulation of greenhouse gases in the atmosphere, such as carbon dioxide (CO₂), methane (CH₄) and nitrogen oxides (NO_x). The contribution of these gases to the greenhouse effect depends on the molecular structure of the gas and is not equal: methane is four times as effective as a greenhouse gas than carbon dioxide; nitrous oxide (NO₃) is 262 times as effective. The term ‘carbon dioxide equivalents’ (CO₂-e) is used to describe the combined effects of these greenhouse gases, against the benchmark of carbon dioxide.

The accumulation of greenhouse gases has been caused principally by land clearing (particularly the clearing of forest and the draining of wetlands) and the burning of fossil fuels, such as coal and oil.

The Tipping Point

The threshold for dangerous climate change is considered to be a rise in the global average surface temperature of 2.5ºC above pre-industrial levels (or an additional warming of 1.7ºC). In order to prevent the increase in the global average surface temperature exceeding 2.5ºC, the atmospheric concentration of greenhouse gases would have to be stabilised at a level below 450 parts per million (ppm) of CO₂-e.

As the current concentration is 430 ppm CO₂-e, staying within this threshold seems unlikely given the ongoing procrastination by governments to initiate appropriate policy responses.

The Predicted Impacts

The Intergovernmental Panel on Climate Change makes some startlingly dire predictions as to what will occur once the tipping point is reached. While a global average surface increase of 2.5ºC does not sound much, it is not evenly distributed. Some parts of the planet are heating faster than others - e.g. the poles are heating more quickly than the equator and the polar ice caps are melting. The loss of sea ice is a major threat to the polar bear. The loss of the Greenland and western Antarctic ice sheets would cause catastrophic sea level rises and may change the pattern of global ocean currents.

The CSIRO has translated the IPCC’s predictions for each region in Australia for a range of temperature increases.

At 2.5ºC we will lose the Great Barrier Reef, large parts of Kakadu and some of our agricultural production, particularly in southern Australia. There will be a 10% increase in the risk of bush fires, and more intense storms and cyclones. Our capital cities will have to deal with ongoing water shortages. Road maintenance costs are predicted to increase by 17% (so expect many more potholes!). For the NSW North Coast, it is predicted that there will be more extreme weather events. There will be:

longer periods of drought, fuelling large bushfires and threatening food supplies; -more intense storm events and larger floods but perhaps a general decline in annual rainfall;
more infections with insect-borne diseases, such as Ross River and Barmah Forest viruses; and
more damage to coastal infrastructure due to a combination of sea level rise and storm surges.

Climate Refugees

Millions of people in low lying countries will be affected as sea level rises. By mid century, it is predicted that up to 90,000 of our near neighbours in the Pacific islands will be exposed to annual flooding. In Bangladesh, 20 million people are expected to lose their homes.

In 2001, Tuvalu requested that Australia commit to accepting 50% of its population in recognition of the impact of climate change on this vulnerable nation. The Australian Government, led by John Howard, refused. This was an indefensible position - with the highest greenhouse gas emissions per capita in the world, Australians have a responsibility towards those most affected by climate change.

The top 10 Myths against Global Warming

Every time there is a report into Global Warming and what could be done about it, there is increased activity from the climate denialists. Usually, to confuse the public, the denialists regurgitate the same old myths that have long been debunked.

So far I have counted 50 myths. Here are just ten of the more popular ones...

Myth 1: There is no consensus on Climate Change

Firstly the denialists can’t even agree on whether the world is warming and then, if it is, they have a number of reasons why, apart from increased emissions. As far as no consensus is concerned, it is only amongst those in denial. The old “31,000 scientists disagree on man-made climate change (the 1998 Oregon Petition)” myth doesn’t stand up. The vast majorityof that 31,000 have absolutely no connection to climate science and of the few who are climate scientists, not one has ever produced any peer-reviewed support. Every time someone says to Tim Flannery there is peer-reviewed work to back their arguments, he asks them to produce it. No one ever has.

Myth 2: Climate models are unreliable

Quite the contrary! Every prediction from the modelling has come true or is unfolding before our eyes. The only ‘mistake’ from models has been when certain factors haven’t been included. A good example is the increased emissions from China which no scientist could have predicted.

Myth 3: Since 1998, the world has been cooling

This is one of the latest myths. The hottest year on record was 1998. Every year since has been in the top twenty hottest years. The same argument could have been used a dozen times in the previous century as cooling took place for a year or two and then continued to rise. The warming trend is ever upward.

Myth 4: 1934 was hotter

No it was not! That only applied to the (then) 48 states of the USA, which only represents less than 2 percent of the world’s area.

Myth 5: It is the sun

For years a number of scientific teams from various countries has been studying the influence of the sun. All conclude that, since 1750, the sun has contributed to less than 4 percent of global warming. Even the Danish scientists who first published the sun theory now agree it is wrong, especially as the sun has cooled over the past few decades while the earth continued to grow warmer.

Myth 6: In the 1970s, scientists predicted an ice age

Wrong again! Following World War Two, industries belched out copious amounts of aerosols which caused a cooling effect. Older people might remember the London and Tokyo smogs and acid rain in Europe. Of all the published scientific studies of that time, 48 predicted a warming world while just 11 warned that, if industry didn’t reform, increased aerosols might produce an ice age. Of course, the media only heard the words ‘ice age’ – makes good headlines. Once industries cleaned up their act warming took off again just as predicted.

Myth 7: The world is gaining in ice cover

Supposedly this is because there is an increase in eastern Antarctica and central Greenland. Since reliable records have been taken, the area of ice and ice thickness have been on the decrease. There is an annual net loss of ice in Greenland and although information from Antarctica is still sketchy there could also be a net loss too as western Antarctica breaks up and slides into the sea. Of the world’s glaciers, over 95 percent of them are retreating. And that is happening on every continent.

Myth 8: It's due to increased volcanic activity

Gas studies at volcanoes worldwide have helped vulcanologists tally up the global contribution CO₂ budget. Globally, volcanoes on land and under the sea release a total of approx. 200 million tons of CO₂ annually. This seems like a huge amount of CO₂ but it is a tiny amount compared to global emissions of CO₂ from the burning of fossil fuels: in 2003, this was 26.8 billion tons. Volcanoes contribute less than 1% to total CO₂ emissions.

Myth 9: CO₂ levels have been higher in 20th century

This myth comes from previous unreliable chemical-based methods to measure CO₂ levels in the air at head height (roughly 2 metres above the ground). The graph produced shows how unreliable this method was. See the graph on the Real Climate website here

Myth 10: The climate has changed before

Well, if we are looking at past changes for guidance, we still have at least 30,000 years to go to get the same changes of the past. Besides, all the studies into past warmings show the world is warming 10 to 12 times faster than at any other time in 650,000 years. It was warmer 65 million years ago (dinosaurs lived at both poles) but most of the biota that currently lives on our planet (including us) weren't around then.

Other myths include: