Climate Change

In essence, some gases in the Earth's atmosphere act a bit like the glass in a greenhouse, trapping the sun's heat and stopping it from leaking back into space to cause global warming.

Without the presence of Greenhouse Gases (GHGs), the earth could not sustain its livable temperature. However, with the rapid industrialisation of the global economy and the resultant release of large volumes of human-generated GHGs, the planet has experienced abnormal levels of warming.

How much any one greenhouse gas influences global warming depends on three key factors: 

1. How much of the gas exists in the atmosphere. Concentrations are measured in parts per million (ppm) - one molecule of that gas in every one million molecules of air;

2. How long the gas remains in the atmosphere, otherwise known as its lifetime; and

3. How effective the gas is at trapping heat, referred to as its global warming potential (GWP), as a measure of the total energy that a gas absorbs over a given period of time (usually 100 years) relative to the emissions of 1 ton of carbon dioxide.

Carbon dioxide accounts for almost 80 per cent of global human-caused emissions, with 40 per cent remaining after 100 years, 20 per cent after 1,000 years, and 10 per cent as long as 10,000 years later. About 90 per cent comes from the burning of fossil fuels, nearly three-quarters of which comes from coal and oil.  Four regions accounted for about two-thirds of global fossil-fuel carbon emissions: China at 31 per cent; the USA at 14 per cent; the European Union at 7 per cent; and India at 7 per cent.  Industrialised countries represent just 20 per cent of the world's population but account for 80 per cent of cumulative carbon dioxide emissions since the beginning of the industrial revolution.

From natural gas production and livestock, methane comprises 12 per cent. It persists in the atmosphere for around 12 years, but its global warming impact is almost 30 times greater than that of carbon dioxide over a 100-year period.

From sources like fertilizers, nitrous oxide represents 6 per cent with a GWP of 270 times that of carbon dioxide on a 100-year time scale, and it remains in the atmosphere, on average, a little more than a century.

Emitted from a variety of manufacturing and industrial processes, fluorinated gases - hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulphur hexafluoride (SF6), and nitrogen trifluoride (NF3) account for 3 per cent, but the GWP for these gases can be in the thousands to tens of thousands. They have long atmospheric lifetimes, in some cases lasting tens of thousands of years. HFCs are used as a replacement for ozone-depleting chlorofluorocarbons and hydrochlorofluorocarbons, usually in air conditioners and refrigerators.

It is standard practice when measuring GHGs to convert all emissions to CO2 equivalent (CO2e). Each gas is measured, multiplied by its global warming potential and then aggregated to give total GHG emissions in CO2 equivalents.

It is estimated that between 1750 and 2019, atmospheric concentrations of carbon dioxide increased by 47 per cent, methane by 156 per cent, and nitrous oxide by 23 per cent. Of all the human-driven emissions of carbon dioxide, approximately half were generated in the last 30 years alone.

In 1997, for the first time, developed nations reached an agreement on actions to cut GHG emissions in an attempt to stabilise global climate change by adopting the Kyoto Protocol with Annex B setting out binding emission reduction targets for 37 industrialised countries and economies in transition and the European Union. Overall, these targets added up to an average 5 per cent emission reduction compared to 1990 levels over the five year period 2008–2012. In 2012, the Doha Amendment to the Kyoto Protocol was adopted for a second commitment period, starting in 2013 and lasting until 2020.

However, in the lead-up to Kyoto, the Howard Government repeatedly threatened that it would refuse to sign any international agreement that did not meet its demands. The result was the ‘Australia Clause’ which granted extraordinary concessions in the last hours of the Kyoto Climate Change Conference. In addition to an 8 per cent increase over 1990 levels of emissions, Australia’s base year emissions were inflated by 30 per cent by the inclusion of net emissions from land clearing. 

Australia signed the Kyoto Protocol in 1998, but the Howard government decided not to ratify it, leaving Australia and the United States as the only major industrialised nations not to do so, despite the fact that, unlike almost every other nation, Australia gave itself the ability to increase its emissions. The ratification came with Kevin Rudd’s victory in 2007 as the first official act of the new Government.  Meanwhile, the sharp fall in land clearing emissions turned Australia’s 8 per cent target into a ‘three-inch putt’.

At COP 15 in Copenhagen in 2009, it was hoped that a new legally binding agreement would be reached to follow on from the Kyoto Protocol. Although that meeting fell short of those expectations, the Copenhagen Accord did recognise the need to reduce global GHG emissions to limit the increase in global temperature to below 2°C.

In the lead up to COP 21 in 2015 in Paris, nations submitted Nationally Determined Contributions (NDCs), which set out each country’s plan for addressing climate change, including a target for reducing GHG emissions and how the countries intend to achieve that target.  The resultant Paris Agreement agreed to the parties ‘holding the increase in the global average temperature to well below 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5°C above pre-industrial levels, recognizing that this would significantly reduce the risks and impacts of climate change’ (Article 2)   with NDCs to be reviewed and updated every five years under the ‘transparency framework’.

Australia’s NDC at the time was to reduce GHG emissions by 26-28 per cent below 2005 levels by 2030, compared to the UK and European Union’s 53 and 40 per cent reduction in emissions by 2030 from 1990 levels, respectively.

The Albanese Labor government’s win in 2022 put in place Australia’s NDC 2030 emissions reduction target of 43 per cent below 2005 levels, as both an emissions budget target and a single year target.  

However, remember that our unique definition of emissions includes land use which is the main sectoral trend driving the long term decrease in Australia’s total emissions and does not include the combustion of Australian-produced fossil fuels which generate at least 5 per cent of global emissions. The carbon emissions from our exports are almost triple the emissions from our domestic use of fossil fuels.  Due to expire in 2003, the recent government approval of Woodside’s North West Shelf gas extension to 2070, all of which will be exported, locks in more than 4 billion tonnes of climate pollution, equivalent to a decade of Australia’s annual emissions, and at a time when our gas exports need to fall by 90 per cent to align with 1.5oC of warming according to the government.  Similarly, studies by the United Nations and International Energy Agency have found that demand for gas will drop as much as 62 per cent and 78 per cent, respectively.  

The next battleground is Woodside’s proposed plans to drill offshore in the Browse Basin some 425 kilometres from Broome, the largest discovered untapped gas reserve in Australia.  But the site is only three kilometres from Scott Reef, a richly diverse coral reef system that lies in both state and federal waters.  Greenpeace has over half a million signatures on a e-petition to stop the project.

Currently, Australia’s emissions are 28 per cent below the 2005 level. This fall has taken place almost entirely in the land sector, together with a decline in the electricity sector as renewable energy has been replacing coal-fired generation.  

The Climate Change Performance Index 2025 ranks Australia a lowly 52 out of 63 countries in terms of emissions, renewables, energy use and climate policy . The Climate Action Tracker rates Australia’s performance as ‘insufficient’.  Our 2030 NDC target of 43 per cent is not aligned with the Paris Agreement target of 1.5°C and needs to be significantly improved to do so. 

In the meantime, in 2023–24, Australian governments have provided $14.5 billion worth of funding and tax breaks to assist fossil fuel industries, a 31 per cent increase on 2022-23 largely due to the increase in the Federal Government’s Fuel Tax Credits Scheme (FTCS) to $9.6 billion in 2023–24 and concessions on aviation fuel growing by $430 million, or 36 per cent to a total of $1.6 billion. Subsidies in the forward estimates increased from $57 billion to a record $65 billion. 

The FTCS refunds fuel excise - a Federal government tax of about 50 cents on every litre of petrol or diesel that you buy - in part, or in full, paid by eligible business users of fuel. Since the implementation of the Fuel Tax Act in 2006, Australia has generated over $147 billion in cumulative fuel taxation to 2021-22 whilst the Federal Government has provided over $95 billion in fuel tax credits.  

As the 18th largest Government expense program in 2023-24, the FTCS means that no fuel tax is payable for vehicles that only drive off-road, such as trucks on mine sites, and a reduced rate of fuel tax is payable for on-road vehicles heavier than 4.5 tonnes, such as semi-trailers, B-doubles, and passenger buses.

The Grattan Institute argues that there is no business reason why larger vehicles should pay less than smaller vehicles – in fact, quite the reverse, since heavy vehicles do far more damage to roads.

Mining accounts for 21 per cent of Australia’s total emissions in 2021 and has played a central role in undermining our progressive emissions reduction goals, rising by 65 per cent since 2005. The growth in emissions is a result of the steadily increasing use of imported diesel in mining equipment.  The government’s approval of seven new coal mine projects in 2023 and 2024 will allow coal mining and exports to continue for many decades to come. 

Moreover, the emissions generated by our exports of coal and gas are not counted in our NDC emissions reduction targets submitted to the United Nations.

The need to reduce our emissions also represents our economic future. For a country that relies on international trade, from 2026, the European Union’s Carbon Border Adjustment Mechanism will impose a charge on the embedded carbon content of certain imports, including fertilizers, cement, aluminium, iron and steel, so the ability to produce goods and services at a lower carbon intensity than our international peers increasingly presents a competitive advantage.

But there is hope. CSIRO’s modelling shows that Australia can use existing technologies to reduce emissions by 52 per cent from 2020 levels by 2030, including reducing fossil fuel use in electricity generation from 70 to 10 per cent by 2030.  After all, we have the highest rooftop solar uptake in the world, accounting for over a quarter of total renewable energy generation.

In September 2025, the Australian government’s NDC announced for the UN climate conference, COP30 in Brazil, was an emissions reduction of 62-70 per cent on 2005 levels by 2035 at its ‘maximum level of ambition’.  The range is below the 65-75 per cent cut advised by the government’s Climate Change Authority as ‘ambitious, but achievable’ in April 2024.

The Climate Council notes that achieving a stronger target of 70 per cent and above would unlock investment and greater economic growth, with modelling indicating that a 75 per cent cut by 2035 could deliver $370 billion to GDP, 69,000 new jobs annually, and $190 billion in export revenue by 2050.

But even at a reduction target of 62 per cent, we have a mountain to climb. 

In the five years to 2023-24, Australia reduced emissions by an average of 9 megatonnes (Mt). In the last financial year, emissions reduced by 7Mt.   To meet the government’s 2030 target, emissions reductions need to more than double that, cutting 16Mt per year. They need to go further still to hit the new 2035 goal, cutting 19-24Mt annually.

And remember the Australia Clause negotiated by John Howard in Kyoto that advantageously included carbon emissions from land use and forestry in our emissions calculations. Between 2005 and March 2025, Australia's emissions decreased by 28 per cent.  However, when you remove the land use sector, emissions have only dipped by a small 4 per cent, led by the switching of coal-fired power stations to renewable electricity. 

Even the government’s own Environment Department is sceptical, reporting that, whilst Australia is on track to reach a 42 per cent reduction in emissions by the end of this decade, just shy of its target, on current projections emissions will fall by just 48 per cent by 2035.

To reach at least the 62 per cent reduction target, the Climate Change Authority modelling includes the need for twenty times as many electric vehicles, twice as many rooftop solar panels and the quadrupling of wind capacity.

We know that we can’t rely on governments and companies to save our species and environment. We all need to play our role.