Climate Change

The following information is from Australia’s most trusted climate scientists, at the Climate Council:

What is climate change?

“Climate is different from weather. When we talk about the Earth’s climate, we are referring to the average weather conditions over a period of 30 years or longer. Weather, on the other hand, refers to what you see and feel outside from day to day (e.g. sunny, rainy).

So climate change is any change in the climate, lasting for several decades or longer, including changes in temperature, rainfall or wind patterns.

The best scientific evidence we have shows that our world is rapidly heating.

Long-term air and ocean temperature records clearly show the Earth `is warming. The global average temperature has already risen by 1.1°C since the time before the Industrial Revolution. This might not sound like a lot, but 1.1°C represents a massive amount of extra heat and energy – the equivalent of four Hiroshima bomb detonations per second.

While the earth’s climate has changed throughout history,  scientists agree that the significant changes we’ve seen over the past hundred years or so have been due to human activities. Recent warming is also happening at a rate that is much faster than previous climatic changes.

What is causing climate change?

The short answer is: the excessive amount of greenhouse gases entering the Earth’s atmosphere due to human activity is causing our climate to heat dramatically. But there’s more to it than that.

Let’s break it down. A certain amount of greenhouse gases (like water vapour, ozone, carbon dioxide, methane and nitrous dioxide) occur naturally. For example, carbon dioxide is produced through the respiration of natural ecosystems (plants), or through the decay of organic matter (biomass). These greenhouse gases act like a blanket in our atmosphere, trapping some of the sun’s heat close to the Earth’s surface. This is known as the ‘greenhouse effect’ – and it makes the planet warm enough for us to live.

But since the Industrial Revolution (which began in the mid to late 1700s), greenhouse gases have built up in the atmosphere, leading to more heat being trapped close to the earth’s surface. This is because Western civilisations began digging up and burning coal, oil and gas on a massive scale. At the same time, agriculture, tree-clearing (deforestation) and the production of waste (landfill) also increased. All of these processes also produce greenhouse gases.

As more greenhouse gases are added to the Earth’s atmosphere, more of the sun’s heat is trapped. This causes the Earth’s average temperature to rise.

Carbon dioxide is the most significant of all the greenhouse gases, followed by methane. Carbon dioxide levels in the atmosphere have increased by more than 45% since the Industrial Revolution and are now the highest they have been for at least 800,000 years.

Reference:

Climate Council – ‘What is Climate Change?’ https://www.climatecouncil.org.au/resources/what-is-climate-change-what-can-we-do/#unique-identifier-1