What is climate change and what can we do about it?

16.10.19 By

Climate science can be complex, and misinformation in politics and the media can make it difficult to sort fact from fiction. Here, we’ve answered eight common climate change questions, including what’s causing climate change, what scientists are saying and what we can do about it. Read on to get up to speed!


1. What is climate change?

2. What is causing climate change?

3. How is climate change affecting Australia?

4. Why do only a few degrees of warming matter?

5. How do scientists know the climate is changing?

6. What are the main sources of greenhouse gas emissions in Australia?

7. What can Australia do to combat climate change?

8. Where can I find out more?


1. 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.

And according to science, our climate is changing quite dramatically – it’s getting hotter.

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 pre-industrial period. 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.

Temperature Anomalies by Country 1880-2017 based on NASA GISTEMP data. By Antti Lipponen.

2. 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 change 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 by plants, or decaying 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, which is trapping more heat close to the earth’s surface. This is because humans began digging up and burning coal, oil and gas, as well as scaling up agriculture and tree-clearing (deforestation), and increasing waste (landfill), which are all processes that produce greenhouse gases.

As more greenhouse gases are added to the Earth’s atmosphere, more of the sun’s heat is trapped and 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.

3. How is climate change affecting Australia?

Australia is one of the most vulnerable developed countries in the world to the impacts of climate change, which include:

We are already experiencing these impacts today, at a rise in temperature of just 1.1 ̊C since the pre-industrial period. In 2019, Australia has seen devastating floods in Townsville, an early start to the bushfire season damaging properties and burning through untouched rainforests in NSW and QLD, and an ongoing drought which has threatened the food and water security of Australians for many years.

The risks to our wellbeing and livelihoods, and to other species and ecosystems, become much more profound as temperatures continue to rise.

Read more about droughts, bushfires and other extreme weather events in Australia here.

4. Why do only a few degrees of warming matter?

A few degrees of warming is incredibly significant.

The Intergovernmental Panel on Climate Change (IPCC) strongly recommends limiting the global temperature increase to 1.5°C, to avoid the impacts of climate change steeply escalating. Even at 1.5°C of global warming, times will be tough. But the impacts amplify rapidly between just 1.5°C and 2°C of temperature increase, as visible in the following infographic.

 

An infographic containing information about the impacts of 1.5 degree and 2 degree warming, and the difference between both.
Adapted from WRI (07/10/18) based on data from IPCC (10/2018).

To avoid the impacts we’d experience at 2 degrees warming, we have no other choice but to limit our warming to 1.5 ̊C. It is still possible, but only if we act now.

If nothing changes, we are on track for a rise in temperatures of between 4-6 ̊C. To put this in context, the difference in temperatures between now and the last ice age was around 4 ̊C.

The Paris Agreement (a universal agreement involving over 190 countries committing to limit global warming to well below 2°C and to pursue efforts to limit warming to 1.5 ̊C) is an important step towards addressing the global challenge of climate change. But with the current pledges that countries have put forward, the world is on track for at least 3.2 ̊C of warming by the end of the century.

Read more about limiting temperature rise to 1.5 degrees here.

5. How do scientists know the climate is changing?

Scientists collect data about the climate by testing a number of things: air and ocean temperature, precipitation (rain, snow), sea level, ocean salinity and acidity, tree rings, marine sediments, and pollen, to name a few.

Ice cores from Antarctica are incredibly helpful in showing how the climate has changed over time, because they can provide a record of what the level of greenhouse gases such as carbon dioxide and methane were in our atmosphere in the past, as well as providing clues about past temperatures. Ice core data stretches back 800,000 years and shows that the concentration of greenhouse gases in our atmosphere over this period never increased so quickly, or by so much, as during this era of human influence.

A graph showing C02 levels from ice cores over 800,000 years.
Carbon dioxide levels in the atmosphere over the past 800,000 years, based off data from ice cores. C02 levels have never been as high as they are now. Source: NOAA

Pulling all of this data together, scientists have concluded that humans have been driving the significant changes in climate that we are currently experiencing. The evidence that supports anthropogenic (human-caused) climate change is vast and includes many lines of evidence published in tens of thousands of peer-reviewed journal articles.

6. What are the main sources of greenhouse gas emissions in Australia?

There are eight major areas (sectors) in Australia responsible for our greenhouse gas emissions:

  1. Electricity (emissions from burning coal and gas to power our lights, appliances and more)
  2. Transport (emissions from petrol and diesel used to power cars, trucks and buses, and emissions from aviation fuel used to power planes)
  3. Stationary energy (fuels like gas consumed directly, rather than used for electricity, in industry and in households)
  4. Agriculture (greenhouse gases such as methane and nitrous oxide produced by animals, manure management, fertilisers and field burning)
  5. Fugitive emissions (gases leaked or vented from fossil fuel extraction and transportation)
  6. Industrial processes (emissions produced by converting raw materials into metal, mineral and chemical products)
  7. Waste (methane from decaying organic matter)
  8. Land use, land use change and forestry (LULUCF) (emissions and removals mainly from forests, but also from croplands, grasslands, wetlands and other lands).

A graph showing Australia's emissions by sector, 2019.
Australia’s greenhouse gas emissions by sector, 2019. Electricity remains the biggest contributor of greenhouse gases in Australia. Source: March 2019 quarterly updates.

Electricity is the largest source of greenhouse gas emissions in Australia, responsible for 32% of emissions. This is mainly because 84% of our electricity comes from burning fossil fuels, the large majority of which (62.3%) comes from coal.

Fortunately, Australia is the sunniest and one of the windiest countries in the world, which means we are perfectly placed to generate our electricity from renewable energy sources, like solar and wind.

Updating Australia’s energy system with renewables and storage is crucial for cutting our greenhouse gas emissions and combating climate change.

7. What can Australia do to combat climate change?

Although we are already experiencing the consequences of climate change today, we also have the solutions to address it.

Australia urgently needs to reduce its greenhouse gas emissions as part of a strong global effort. But currently, emissions in Australia and globally are still rising.

The IPCC has suggested that the world must cut carbon dioxide emissions to net zero by no later than 2050 to have a chance of limiting warming to 1.5 ̊C. This means that global carbon dioxide emissions have to start dropping now, and be on a path to fall by at least 45% below 2010 levels by 2030. Methane and other greenhouse gas emissions must drop steeply as well.

For this goal to be achievable, we have to start driving down all emissions across all sectors now.

 

A graph of Australia's greenhouse gas emissions from 2009 to 2019.


Australia’s greenhouse gas emissions (excluding land use) have been rising consistently for five years since 2014, and are at the highest levels on record.

Here are the easiest, most efficient and cost-effective ways for Australia to reduce its greenhouse gas emissions:

1. Electricity
Rapidly transitioning away from fossil fuel generated electricity to renewable energy and storage technologies is the quickest and cheapest way to reduce emissions. In Australia and many other countries, new renewable energy is now cheaper than new coal (over its lifetime), and global investment in coal has plummeted by 75% in three years.

2. Transport
Avoiding dangerous climate change doesn’t start and end with changing electricity. We also need to electrify our transport systems – like buses, cars, trains and trams – and power them with 100% renewable electricity too. Transport makes up around 19% of Australia’s greenhouse gas emissions, but these emissions can be reduced by: improving public transport’s quality, efficiency and accessibility, encouraging active transport (such as cycling and walking), and building infrastructure (like vehicle charging stations), to encourage people to use electric vehicles.

3. Agriculture
Agriculture contributes roughly 13% of Australia’s emissions, and deforestation accounts for around 9% of Australia’s emissions. But climate solutions like reforestation and regenerative agriculture can increase how much carbon is stored in soils and vegetation, removing carbon dioxide from the atmosphere.

4. Fossil fuels
Australia needs to actively transition away from fossil fuels like coal, oil and gas, including those we export. As the second largest exporter of both thermal coal (which is burned to generate electricity) and gas, Australia has a huge influence on global emissions and the fossil fuel market. If we include all the fossil fuels that Australia exports, Australia is the fifth biggest polluter in the world – so we’re a big deal when it comes to climate change. Australia should not approve any new fossil fuel projects, and must actively phase out existing projects to reduce emissions. This process has to support fossil fuel-dependent communities and workers – and make sure that they have opportunities to move into other industries.

8. Where can I find out more?

The Climate Council has created a range of science-backed materials to further explain the causes, impacts and solutions to climate change. Take a look at our Reports, Videos and Infographics.

These might also interest you:

What can YOU do to tackle climate change?

Watt’s watt? A guide to renewable energy capacity and generation

Climate Action: 6 reasons to feel inspired not defeated

Let’s Get Something Straight – Australia Is Not On Track To Meet Its Paris Climate Target

Deforestation and Climate Change

How climate change is damaging Australia’s economy