I love swimming in the ocean, watching the wildlife, which is a bit strange for someone who grew up on a farm and still lives on one (and not by the water's edge). I am a bit of a nerd, who loves the natural world, sci-fi and fantasy books and wargaming.
Questions answered by this expert
What is climate change?
I have been asked a lot about how climate change works – what is it, how does it happen, and what happens to the Earth with global warming. To answer this I’ll start by talking about the difference between weather and climate. As I’m sure you know, weather is the changes in temperature, rainfall and wind that we see outside from day to day, while climate refers the usual weather of a place. Tasmania has a cool temperate climate overall, but the west coast has a wetter climate than the east coast, and the central regions have a cooler climate than the coast. The Earth also has a climate; Earth’s climate is what you get when you combine all the climates from around the world together.
Climate change is a change in the usual weather of a place. While the weather can change in just a few hours (as it often does in Tassie!), climate change occurs over many years. And in fact the Earth’s climate has always been changing. As I’m sure you know, there have been times in the past when the Earth was much hotter than it is today, and also times when it has been much cooler. But an important difference with climate change caused by human activities is that the change is occurring much, much faster than we have ever seen before.
There are lots of different things that can cause climate to change – volcanic eruptions, changes in the world’s oceans, and changes in the activity of our sun. Climate change caused by humans is due to the gases we release into the atmosphere – particularly carbon dioxide from burning fossil fuels, but also methane and other gases. These gases cause a green-house effect which traps more of the sun’s energy in Earth’s atmosphere and so warms the planet. This warming also causes changes in other features of our climate such as rainfall.
Earth's temperature will keep going up for at least the next 100 years. This will cause more snow and ice to melt and sea levels to rise. Some places will get more rain and others will get less rain. There will be more heatwaves and some places might have stronger storms. The sooner we can stop emitting greenhouse gases and implement solutions to take excess carbon dioxide out of the atmosphere, the better chance we have of minimising the impacts of climate change on our Earth.
What causes the earth to get hotter due to climate change?
How and why have global warming and climate change occurred?
The how and the why of climate change are very tightly linked, so tightly linked people as far back as 1896 had figured out the basics of how it works. Earth’s atmosphere keeps the world warm by trapping heat. It does this in a way similar to the way a greenhouse works (thus the name “greenhouse effect”). Sunlight (and warmth) can come through the atmosphere in the day time and warms up the land and sea areas. At night cooling occurs, with the heat escaping into the atmosphere, some of that leaks out into space again, but not all because the atmosphere traps some of the heat. The key bit of the atmosphere that traps the heat are the greenhouse gases.
Natural greenhouse gases are water vapor, carbon dioxide, methane, ozone and nitrous oxide. These chemicals are an important part of the world’s natural cycles. They cycle between the atmosphere, the ocean, soils and rocks. Human activities have changed those cycles, meaning more greenhouse gases have entered the atmosphere, trapping more heat and leading to global warming and climate change.
Many human activities influence climate relevant cycles, but two of the most important are to do with carbon dioxide and methane. Fossil fuels contain carbon dioxide locked up millions of years ago, by bringing it to the surface and burning the fossil fuels human activity short circuits natural weathering and other cycles, creating one of the major sources of the excess carbon dioxide that is creating climate change.
Agriculture is also a major contributor to climate change, producing about a quarter of all current greenhouse gas emissions. These emissions come from the fuels used by farmers, but also because of emissions from rice paddies and livestock, which produce methane. A particularly powerful greenhouse gas, over a 20-year period methane is 80 times more potent at warming than carbon dioxide. On top of this, the removal of native vegetation, like forests, to create space for agriculture reduces the amount of carbon drawn out of the atmosphere and stored in trunks and roots as trees grow (known as sequestration).
As you can see there are many interconnected ways that human activities are influencing the biogeochemical cycles of Earth and thereby contributing to climate change.