climate change basics: What is climate change?

WHAT IS CLIMATE CHANGE?  (from the ACF website)

Climate change is the consequence of unchecked pollution. When carbon emissions caused by human activity enter the air they have  dangerous effects on the environment, the economy, and our wellbeing. But just as humans cause it, we can halt its progress.

What are the causes of climate change

Climate change is caused by trapping excess carbon in Earth’s atmosphere. This trapped carbon pollution heats up the atmosphere and the earth’s surface, altering the Earth’s climate patterns. The largest source of this pollution is the burning of fossil fuels (such as coal and oil) for energy.

While carbon has entered the atmosphere for millions of years through natural events such as forest fires and volcanoes, the burning of fossil fuels and clearing of land has resulting in the highest levels of greenhouse pollution in our atmosphere in the last 800,000 years.

Why is our climate is getting warmer?

The Earth’s atmosphere has evolved to retain sufficient warmth from the sun to encourage a healthy, dynamic ecosystem, while shielding us from its harsher effects. The introduction of huge amounts of excess pollutants thickens this blanket of protective gases, causing heat to remain trapped within, rather than harmlessly escaping skywards. These gases can remain in our atmosphere for up to 90 years, contributing to long-term warming.

As the world warms, there are flow-on effects that can make things worse. For instance, warmer water melts polar ice caps each summer. Sea ice normally reflects heat from the sun, while water absorbs it. Less ice means more heat which in turn means less ice, leading to a cycle of warming from which it is hard to escape. Temperatures are already rising quickly, with the last decade being the hottest on record.

Why this is bad

Decades of climate science has found that if we fail to reduction carbon pollution, climate change will have profound impacts on our planet. Climate change isn’t just a temperature change

Sea level rise affects coastal property, people and ecosystems. By 2050 and a 4°C or 0.48m sea-level rise, 130 million people per year are expected to be flooded, 3/4 of them in Asia.

Warming also affects rainfall and seasons. This in turn threatens food security. Inaction in cutting emissions and a temperature increase of just 4°C would cause rice and maize yields in Asia to drop by 30%, cutting off food supply to millions. Warming also increases the severity of extreme weather events such as tropical cyclones, bushfires, droughts and flooding.

What this means for us

Australia’s environment and economy are particularly vulnerable to the effects of climate change. Some of these effects are already occurring.

The magnificent Great Barrier Reef is already experiencing severe bleaching due to a 0.4°C rise in water temperature. Each year, about 60% of our reef is subject to some bleaching. Professor Ross Garnaut pointed out that we are “likely to see, by mid-century, the effective destruction of the Great Barrier Reef”.

Changing weather patterns are making Australia — already the driest inhabited continent — even drier. The result has been historically severe droughts and nationwide water shortages. Droughts could occur twice as often across the Murray-Darling Basin, Australia’s foodbowl.

Likewise, some of Kakadu’s unique wetlands are under threat from rising sea levels. Ocean salinity is only 20cm away from devastating this precious natural landmark. Already, two-thirds of Kakadu’s melaleuca forests have been killed by increasing salinity. If sea levels rise by 60cm, 90% of Kakadu will be hit hard, yet on current trends, things will be much, much worse.

The challenge facing us now requires courage to meet it. We need to drastically reduce the amount of pollution we create. We need to fundamentally change the ways we produce and use energy.

Price on pollution

Australia now has laws that charge our largest polluters for the pollution they create, but that is only a step in an ongoing process. The price on pollution will cost the average Australian household only $9.90 a week, and many will be better off after receiving government compensation. The price of not acting on climate change will be far greater than an individual cost of $9.90 a week.

We need to switch to clean, renewable sources of energy, and end our reliance on inefficient fossil fuels and wasteful energy habits. Renewable energy is available now. It is safe for the environment and good for our economy. By dealing with climate change, we can make Australia a world leader in renewable energy, create thousands of jobs and ensure clean, healthy air for our children and future generations.


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