Thank you for such a thought-provoking question! I would argue that plastic isn’t destroying our planet, rather, the ways in which we use plastic, are. Before going into the negative impacts of plastic, I should note that in many cases, plastic can be lifesaving: Plastic is found in airbags, seatbelts, and car windscreens (laminated windscreens can stop glass from shattering during an accident). It makes modern technology possible. Indeed, it is found in mobile phones, computers, and scientific equipment! However, we need to be mindful of how we use plastic. We don’t really know how long plastic takes to break down in the environment (we describe this as biodegrading), and most plastic never truly biodegrades! As a planet, we produce about 380 million tonnes (1 tonne = 1000 kilograms) of plastic waste every year, and half of that waste is single-use plastic (items that we use once, and then discard). 

Before answering how plastic affects Earth, I want to highlight that there are different types of plastic. Polyethylene terephthalate (PET) is a type of plastic that does biodegrade. This is because a bacterium known as Ideonella sakaiensis consumes PET as a food source! However, bacteria are small, and can only eat so much. In the absence of bacteria, PET can take 450 years to break down (that’s 5,400 months, or 21,600 weeks, or 1,971,000 days!). Another type of plastic, polyethylene, never breaks down – and it is plastics like this that are particularly bad for the planet. These plastics become brittle over time, and break into smaller and smaller pieces until they become a microplastic (plastic that is so small, we struggle to see it without a microscope). We are finding plastic associated chemicals everywhere – even in the milk of whales! Unfortunately, this has dire consequences. When milk is contaminated with chemicals, it affects animals that feed on that milk. We have started to observe whale calves (and other animals) dying from plastic contamination.   

Plastic is also made with fossil fuels, meaning that its production disproportionately increases atmospheric pollution and contributes to climate change. You are all probably aware of how fossil fuels can harm the planet, so I will change focus a little and highlight another consequence of our plastic use: The transformation of Earth’s layers. In the most basic sense, Earth can be divided into three layers. These layers are the core (the hot ball of lava in the centre of our planet), the crust (the thin layer, or skin, of the planet. The crust is where humans, plants, and animals exist), and the mantle (everything between the core and the crust – if Earth were an Oreo, the mantle would be the white stuff). Because plastic is so hardy, it has a good chance of fossilising once it is buried! The effects of fossilised plastics are yet to be common knowledge (scientists are still working to understand what it means for ecosystems), but there is no doubt that it will significantly alter some environmental processes.  

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.