This is a great question, but one that science can’t fully answer yet. There are several ingredients necessary for fire, which means it is often difficult to say that a particular fire was caused only by climate change. For bushfires to occur, there needs to be:

• fuel to burn, which is typically leaf litter and twigs, grasses, shrubs and trees;
• the fuel needs to be dry enough to catch on fire;
• an ignition source, such as a camp fire that somebody failed to put out, lightning, or a downed powerline, and
• fire weather: typically hot, dry, windy weather that causes a fire to spread quickly. 

Because all these ingredients are required for a bushfire, it is difficult to say how many fires are specifically caused by climate change. We do know, however, that climate change is affecting each of these ingredients. Climate change is leading to changes in plant growth (fuel) and causing fuels to dry out more quickly because the air is hotter and drier. Climate change seems be leading to more ignitions from dry lightning (lightning that occurs when it is not raining). Climate change is certainly causing more dangerous fire weather (hot, windy weather) and fire seasons that start earlier in the year and finish later.

So, although science cannot yet say how many fires are caused by climate change, we can be confident that climate change is leading to more large forest fires around the world.

This is an excellent question! And a complicated one to answer because it involves lots of different parts, but let me try! Lots of you might have heard that globally, we are trying to limit global warming to 1.5°C in the next decades. Whilst this might sound like a small number, it actually reflects an average of temperature increases and decreases all around the world. The reason that 1.5°C has been identified is that if we go past this temperature rise the world is likely to experience extreme events such as heatwaves, forest fires and flooding more frequently – but the world won’t be uninhabitable. 

The world will not become uninhabitable because we will be able to adapt – already, lots of people are adapting to climate change around the world. For example, in Australia we are managing forests differently to prevent big burn events from happening. Scientists and Indigenous people are working together to reduce forest fires and protect natural environments, wildlife, and people. Australia is also protecting important ecosystems such as the Great Barrier Reef – the National Reef Restoration and Adaptation Program is working to help the reef adapt and recover from the impacts of climate change. 

We are long way away from an uninhabitable temperature! It could take many thousands of years for temperatures to be too severe for people to live. But we want to protect people today and future generations from extreme weather events and other impacts of climate change. To do so, people around the world will need to act fast to make changes. If we can manage to greatly reduce global greenhouse gas emissions (such as carbon dioxide, CO2, by driving less or by burning less fossil fuels like coal) we can limit climate change. 

Plants and animals are threatened by lots of things like habitat loss from land clearing, or being hunted, fished or harvested. On top of these pressures are climate change impacts.  

Because there are so many interacting threats to biodiversity, we haven’t yet attributed many species’ extinctions only to climate change. Species that we have lost to date from climate change are species that occur only in one place, so they are very rare, and those places are exposed to immediate climate impacts such as flooding and sea level rise.  

The Bramble Cay Melomys was an Australian rodent that occurred only on one island in the Torres Strait. In 2016, it became the first recorded species extinction attributed to human induced climate change. The small sand island it lived on was affected by sea level rise and storm events. The extinction record by the State of Queensland said that extinction was caused by "ocean inundation of the low-lying cay, very likely on multiple occasions, during the last decade, causing dramatic habitat loss and perhaps also direct mortality of individuals" (1). There are likely other species that have been lost to a similar fate.  

The IUCN Red List of species is the best source for understanding global threats to species. Expert have listed climate change as a cause of decline for 19% of all species listed as near threatened or threatened. Climate change impacts that threaten species include increases in storms, flooding, extreme temperatures, drought, and sea level rise.  

As an example – Hooded seals are a species threatened directly by climate change. Their population has dropped in abundance by 90% in the northeastern Atlantic Arctic over the last 20 years. This decline is attributed to loss of sea ice which has reduced the number of places available for resting and raising pups.  

Looking into the future – One study estimated that if we follow our current, business-as-usual trajectory of climate change, which is projected to lead to a 4.3°C temperature rise, climate change would threaten one in six species (16%). This could as much as double our extinction rates.  

This is one of many reasons why people are calling for governments to limit climate change to 1.5°C, by ‘decarbonising’ our economy – or stopping emissions of CO2. If we do this, we can reduce the rates at which plants and animals become extinct. 

The answer to this question is not straightforward as the emissions from a school (or any other organisation) depend on the size, location, and resource use for each school, among other factors. For example, a small school is likely to have lower emissions than a large one, but a large school that produces its own electricity via solar panels would likely have lower emissions than a small school using electricity from the grid.

When calculating a carbon footprint (the amount of greenhouse gas emissions released by an organisation or individual), it is important to include both direct and indirect emissions. For example, driving a car produces direct emissions from the use of fuel by the car, while using a computer produces indirect emissions from the use of electricity generated at a coal-fuelled power station. Similarly, a piece of paper has associated indirect emissions from the production and transport of the product.

More and more organisations, including schools, are measuring their emissions and developing plans to reduce these emissions. To provide an idea of the magnitude of emissions for a school, Corinda State High School in Queensland reported 1,075 tonnes of carbon dioxide equivalent(CO₂-e) for 2020 in their Public Disclosure Statement for their carbon neutral certification by the Commonwealth Climate Active Carbon Neutral Standard. This is the equivalent of driving 488 fossil fuel burning cars for a year.

Carbon dioxide equivalent is a measure used to compare the emissions from various greenhouse gases by converting amounts of other gases to the equivalent amount of carbon dioxide. For example, the global warming potential of methane (a greenhouse gas released by cattle or decomposing waste in landfills) is 25 times higher than carbon dioxide, therefore 1 tonne of methane would equal 25 tonnes of CO₂-e.

Climate can impact Tasmania sea horses in many ways. To understand the total impact, we need to think about not only what warmer water will do to the seahorses themselves, but also the things the eat and the things that eat them! We are not exactly sure how this will play out, but one thing is for sure: For reef-dwelling animals that enjoy colder water for any number of reasons, there is not much space to move furth south in Tasmania before hitting the inhospitable Southern Ocean.

Specifically, we have seen a nearly 60% drop from in the population of the Weedy Seadragon in Southern Tasmania. However, it is important that this could be caused by other human impacts like poaching. And some evidence does suggest sea horses will be able to adapt to warmer waters as they already live in quite a large range of temperature conditions.

The surface of the earth has warmed by about 1 degree over the last 100 years. We know this because humans have been making measurements of land and ocean temperatures for several hundred years. By carefully combining these measurements and using mathematical methods to fill in gaps, scientists have been able to track how earth’s temperature has changed since about 1850. To be more precise and consistent, climate scientists have agreed to standardise how they talk about warming. So rather than look at 100 years ago, they use the average temperature between 1850 – 1900 as the background starting point. At the other end, the latest reporting compares this starting point to the average temperature from 2011 – 2020. Between those two time periods (which is slightly more than 100 years), our best estimate is that the earth’s surface has warmed by 1.09 degrees. The earth’s surface is made up of land and sea, and if we break it down, we see that the land surface has warmed more than the sea surface- the land has warmed by 1.59 degrees, while the ocean surface has warmed by 0.88 degrees.

We know the most about how Earth’s surface temperature has changed, because that’s where we have the most measurements from. However, other parts of the earth are also warming. In the atmosphere, temperatures have increased throughout the lower part of the atmosphere, known as the troposphere (roughly from the surface to 15 km above). The ocean has warmed down to at least 2km below the surface, although the strongest warming is at the ocean surface.

What this all means for us is a great question. First, global surface temperatures might not mean that much to us, as we only live in one place. The data for Tasmania, compiled by the Bureau of Meteorology (you can have a look at graphs here) show that Tasmania has followed the global trend pretty closely, and has warmed by about 1 degree over the last 100 years. 1 degree of warming doesn’t sound like very much- after all, a high of 18 is not that different from a high of 17. Certainly in Tasmania this temperature rise hasn’t pushed us to the edge of what the human body can endure. But a rise in temperature is associated with other changes, to things like bushfires, droughts, floods and the movements of plants, animals and even diseases. These have all changed over the past 100 years and we’re still studying how much, how this has affected us and to what extent the changes can be attributed to climate change.

Another thing this means for us is how our ability to explain the temperature change that has occurred gives us confidence that as scientists we have quite a good understanding of how climate works. The graph below shows that the observed warming (black line) is reproduced quite well by climate models, but only if the models include human (red and blue) and natural (green) causes- the natural causes alone can’t reproduce the temperature rise that’s occurred over the last 100 years. This means we can trust the predictions made by the climate models, and this trust should give us confidence to take action to prevent the worst outcomes.

The short answer to this great question is: not as much as we’ll need to invest if we don’t make a drastic change! In the past, the cost of changing the way we do things has been used as an argument for not acting on climate change, but there are costs on both sides of that argument (that is, there is a cost to acting but there is also a cost to not acting). Climate change is making disasters like extreme bushfires and droughts more common, and these kinds of disasters already cost Australians a lot (approx. $3 trillion from 2010-2019!). These costs, which relate to damage and lost income, are going to increase a lot if we do not take urgent action on climate change.

Some people have tried to estimate how much money the world would need to spend to stop climate change, and their estimates range from $300 billion (the cheapest option!) to $50 trillion! Both of these amounts are huge and hard to imagine. The big difference between the cheapest and most expensive estimates also show us that working out exactly how much investment is required is a really hard maths problem! It’s hard because the final cost will depend on lots of things, like whether people agree on what to do, who should do it, and when, but also on how quickly we all make the drastic changes that are needed. For example, we know we need to shift from using fossil fuels to renewable energy, but the cost of doing it quickly (which might include governments paying some of the costs for people to install solar power, big batteries and other renewable options at their homes) might be really different from making that change slowly (which might mean that companies and governments waste money building or upgrading fossil fuel buildings that they can’t use because fossil fuels are banned).

Importantly, we need to remember that money we spend now to get ready for the challenges of climate change will benefit young people alive today and all of the people that come after us, as well as natural systems like our coasts and beaches, wetlands and forests. Investing in drastic change is definitely ‘worth it’, because this is an investment for all of us, and for our children’s children, and for the places that we love the most.

Thanks for asking about Tasmania’s contribution to climate change!   

To assess states’ or countries’ contribution to the gases that create climate change, climate scientists try to measure how much greenhouse gas is release into the atmosphere because of human activities. Trapped greenhouse gases cause warming of the atmosphere and the surface of the Earth.  

Most carbon emissions come from burning fossil fuels or wood for transport, heating our homes, and industrial processes. Methane is emitted by agriculture and waste.  The other category is land-related emissions. Land-related emissions simply mean the stored carbon lost through forestry activities such as logging and land clearing for agriculture.  

Tasmania is unusual in Australia because we generate 100% renewable electricity from hydropower and wind turbines. If we look at Tasmania’s emissions, agriculture made the biggest contribution of 2.4 megatonnes of greenhouse gases in 2019 (that’s the weight of 400,000 elephants), followed by transport, at 1.8 megatonnes, and burning fuels for industrial operations, together with household heating and cooking, at 1.75 megatonnes..  

The good news is that despite all the emissions that have been released by human activities, Tasmanian forests neutralize all these emissions! Trees breathe in carbon dioxide and turn it into carbon and oxygen. The latest data (2019) tells us Tasmania is currently removing more carbon dioxide from the atmosphere than it is producing. 

But that’s not the whole story – the reporting doesn’t count the emissions from forest that burns in bushfires. As the climate heats up, bushfires are more likely to happen, so we need to make sure we use healthy fire and forestry techniques to prevent out-of-control fires that could be a major cause of greenhouse gas emissions. Let’s give a big shout out to Tasmanian forests and make sure we protect them!! 

On average, the global sea level is expected to rise by about 40 cm, nearly half a meter, by 2050. Of course, sea level rise depends on how much carbon dioxide emissions are released by humans. However, in 2050 there actually isn’t much difference between predictions of the best (RCP2.6) and worst (RCP8.5) case scenarios. It is not until after 2050 that their paths really diverge. That’s because it takes a lot longer for the ocean and ice on the planet to respond than the atmosphere.  

Interestingly, the amount sea level rise will be quite different depending on where you are.  In Sydney, for example we might expect .2 m by 2050, but in NYC it could be up to .45. This is because there is a lot more land in the northern hemisphere and all that land is very heavy. Its weight actually pulls water to the north via the force of gravity. 

To calculate how much land that increase in sea level will flood, you also need to consider how far above sea level the coast line is. Over all, once you consider the shape the coastline around the world, we could be looking at 4.3 million acres underwater. That land contains the homes of 40-150 million people. 

This is an interesting combination of questions. So, let’s start with ocean pollution. There are mainly five types of ocean pollution: increasing acidity of the ocean, addition of plastic waste, increasing concentration of chemicals, noise due to human activities and addition of toxic products. Each of these contributes in varying amounts to ocean pollution and threatens the marine environment and life. As of today, researchers have declared around 500 marine locations as dead zones (where marine life cannot survive) that covers approximately three and half times the area of Tasmania (245 thousand km²). We can reduce this by recycling day-to-day materials, reducing usage of plastic stuff, avoiding putting stuff that is not recommended to dump in our toilets, volunteering for beach cleaning activity etc. You can also learn other cool facts about the ocean pollution on this website.

In the case of sea level rise, I am delighted to inform you that Tassie is safer than other parts of the world. In 2016, CSIRO said to the Tasmanian Department of Premier and Cabinet in their report that if will not do anything to reduce our carbon dioxide emissions then Tassie is expected to experience on average rise of 0.3 meters by 2050 and 0.8 meters by the end of this century compared to what it was in 2010. In this case, some parts of Tassie such as Hobart, Launceston, Devonport, Burnie, Kingston, Bicheno, St Helens and Bruny Island are likely to experience reduction in their livable size. It is important to know that sea level change is a complicated process to understand. And its impact on our life depends on factors such as how often an area experiences an increase in local water level because of heavy rain, or tide or storms etc., for example. I hope this answers your questions.

We had a few questions about the future of our atmosphere! See Dr Stuart Corney's answer about what the atmosphere will be like in 100 years below.

Climate change is affecting all of our lives in many different ways.

If you live in Tasmania, you will see it in our landscape. Sea levels are rising, which means we are losing some wetlands and beaches. This can also affect our communities. In the next few years, low-lying houses and roads are likely to go underwater. We're also getting more very hot weather days, that mean frequent and severe bushfires, which threaten some people's homes, and can destroy forests and wildlife. Because of climate change, some places, like alpine and peat bog areas that have never burned before, are starting to dry out and burn in bushfires. This means that we could lose some rare Tasmanian plant and animal species.

If you like to fish, you might find that there are different kinds of fish coming into the seas around Tasmania for you to catch - but if you like to dive or snorkel you may not see Tasmania's giant kelp forests for much longer.

By the time you are old enough to learn to drive, you are likely to drive an electric car - we need to make sure that all our transport is powered from renewable energy. And when you get a job, there will be lots of jobs that are there because of climate change - jobs in renewable energy production, jobs in climate science and climate response, new types of fisheries and agriculture and that are there because of climate change, and many more.

We will all need to be a part of adapting to climate change - and there are many opportunities to choose how you can be part of the change we need. Have a look at the What can I do? page for some more ideas.

Climate change and its causes will affect your generation in many different ways, in Australia and elsewhere. These include rising average temperatures, more frequent and severe storms, floods and bushfires, and extinction of plants and animals. The loss of topsoil from drought, flood and wind and unpredictable weather will affect farming and could cause more frequent and severe famines. This could lead to increasing political tensions in some countries around access to resources. People and governments will need to spend more money on safety and preparedness. These impacts are all related to one another.  

A lot of produce will become more expensive as environments change. This includes coffee and honey, and even some vegetables, fruits and meat. Campfires, burn-offs and open-flame barbeques would be restricted for longer parts of the year as fire bans become increasingly common. Take the example of the 2020 bushfires. More than 3 billion animals were impacted, forests were damaged or destroyed, and human tragedies included loss of life, health, homes and livelihoods. Crises like this would be repeated in increasingly worse fire seasons, meaning bigger and bigger expenses for fire preparedness. Taking action on climate change will not stop these impacts entirely, but it can reduce them.

Climate change and its causes impact more than the natural environment. They have knock-on impacts in health. Air, water and soil pollution will continue to cause health conditions and worsen existing ones like cardiovascular and respiratory diseases as well as cancers. While these outcomes are less common in Australia, they happen here too. People in poorer communities with fewer support structures are impacted most. Your generation will see these impacts in your lifetimes. In fact, you already have. Increased exposure to new infectious diseases in the environment has also been linked with climate change, meaning epidemics and pandemics may be a thing of the future and not just the present.

While these impacts cannot be stopped completely, there is so much that can be done to avoid the worst of it. If we rapidly reduce the greenhouse gas we emit, we can improve the future for your generation and the generations who follow you. Action on climate change now will play an important part in your future quality of life, and in the lives of many others around the world in your lifetime.