The Effects of Human Activity
The effects of human activity on the earth's climate has been researched for almost a century. Evidence has concluded that carbon dioxide (CO2) emissions from the burning of fossil fuels is the primary contributor to global warming. In the last 800,000 years scientific evidence demonstrates that environmental changes have never occurred before at the pace it is today. The following information details key factors driving rapid climate change and provides further perspective on CO2 and the importance of this life-giving and yet [environmentally] disruptive gas.
1.6 Trillion Tonnes of Carbon Dioxide
Since the Industrial Revolution, an estimated 1.6 trillion tonnes of Carbon Dioxide (CO2) have been emitted into the earth’s atmosphere through the burning of fossil fuels. CO2 emissions have warmed the planet by an average of 1.18 degree centigrade above the average temperature from 1850 to 1900. Critically, the majority of CO2 gases emitted through the burning of fossil fuels since 1751 remain in our atmosphere and oceans.
Carbon Dioxide
Carbon dioxide is the earth’s most important greenhouse gas due to its molecular structure. CO2 is highly effective at absorbing and radiating heat - unlike nitrogen or oxygen, which are poor conductors. Greenhouse gases (GHGs) like CO2 absorb heat radiating from the Sun and re-release the heat in all directions - effectively trapping it inside our atmosphere. This is known as the "Greenhouse Effect". Increasing CO2 levels diminish the earth's ability to “cool itself off” by not allowing the transfer of heat back into space.
423 ppm
CO2 is measured in Parts Per Million (ppm). In the last 100 years, fossil fuel burning has driven CO2 levels from 280 ppm to 423 ppm. Over the previous one million years, CO2 levels have oscillated between 180 ppm and 300 ppm as the earth transitioned in and out of ice ages. The dawn of agriculture and human settlement was only established when CO2 and the earth’s climate stabilised at the end of the last ice age, around 10,000 years ago.
Our Atmosphere
Our atmosphere is made up of 78% nitrogen and 21% oxygen - with the remaining 1% made up of elements that include argon, carbon dioxide and trace elements such as neon, helium, methane, krypton, ozone, carbon monoxide, and water vapour. With only 0.04% (419 parts per million) of the atmosphere containing carbon dioxide, many critics of man-made climate change question how such a small amount of the atmosphere can have such a consequential effect on global warming.
CO2 is Important
Greenhouse gases like CO2 occur naturally in our atmosphere and are essential to the survival of humans and other living things. CO2 retains some of the sun’s warmth (and stops it from radiating back into space) and this allows our planet to be liveable. It is important to recognise that without CO2, the Earth's natural greenhouse effect would be too weak to keep the average global surface temperature above freezing.
40 Billion Tonnes
Most of the CO2 emissions directly related to the burning of fossil fuels have steadily increased from zero in the early 1700's to 37 billion tonnes in 2023. Overall, the net global increase of C02 in 2023 was 40 billion tonnes and this increased by 1.1% compared to 2022 levels.
Evidence
Scientific evidence shows that over the last 66 million years, CO2 levels and global earth temperatures are related, with higher C02 levels correlating to increased earth temperatures. Antarctic ice cores provide accurate readings of CO2 levels over time, because tiny bubbles of air become trapped inside ice layers, and these pockets of air document atmospheric conditions when each ice layer was formed.
Why is CO2 Increasing?
The burning of fossil fuels, combined with the large-scale removal of forests, has seen a rapid increase in atmospheric CO2 to levels not seen in the last 800,000 years. Population increases combined with improved standards of living have utilised coal and oil as the dominant energy sources. And whilst there are many positives to oil and gas, the CO2 emissions they emit are driving up average atmospheric temperatures.
392 Million Tonnes of CO2
Australia recorded annual CO2 emissions of 392.28 million tonnes directly related to emissions from the fossil fuel industry (excluding land use changes) in 2022. Australia is responsible for approximately 1.1% of ALL fossil fuel emissions, globally. Meaningful actions taken by Australians to reduce their carbon emissions have a direct effect on lowering Australia’s overall CO2 emissions footprint.