This page in brief
To do something about it, we need to know the causes.
This page outlines the scientific findings that increased human activity since the industrial revolution is the main cause, and then looks at the ways we can ameliorate this situation without too great a cost.
Climate change is caused by an increase in the earth’s temperature. Scientists have concluded that the main cause of the temperature increase is an increased concentration of the gases water vapour, carbon dioxide, methane, nitrous oxide and chlorofluorocarbons in the atmosphere. These gases trap the sun’s energy which reaches the earth’s surface, and reduce the amount reflecting back into space, thus warming the earth’s surface.
But the earth’s temperature has changed in the past, so could the causes now be natural?
Possible natural causes are volcanic activity, a change in the energy from the sun and variations in the earth’s orbit around the sun.
However this is no evidence of dramatic changes in any of these factors sufficient to account for the dramatic temperature increases of the past few decades.
- Solar radiation has remained close to constant for the past 3 centuries.
- Volcanoes deposit greenhouse gases into the atmosphere, but carbon isotope studies show that the volume is a small proportion of the total.
Scientists are now 95% sure that the major source of the increased gases is human activity, which has significantly increased these gases since the industrial revolution. The major causes are:
- the burning of fossil fuels for energy and heat generation, including residential and industrial use (about 60%) and transport (about 15%), and
- agricultural and other land use activities (about 25% – land clearing, fertiliser use, flood irrigation and stock all produce greenhouse gases).
Sceptics vs science
Sceptics are still arguing this point, but the consensus of scientists and scientific organisations around the world now supports the conclusion that the major causes are human, not natural. This includes reputable organisations such as the US national Aeronautics and Space Administration (NASA), the Australian Commonwealth Scientific and Industrial Research Organisation (CSIRO) and the European Academy of Sciences and Arts.
For more on this, see A climate change conspiracy?
To reduce the future impacts of climate change, we obviously need to reduce the amount of greenhouse gases we put into the atmosphere – in particular, we need to reduce the amount of carbon. There are many ways to do this.
Develop less polluting energy generation, transport and other industry
The generation of electricity and heat using fossil fuels is the major source of greenhouse gases. Thus the biggest single step we can take is to reduce our use of fossil fuels, especially to keep coal in the ground and transition from oil gas and coal to renewable energy. There are many forms of renewable energy:
- solar – together with battery storage to provide continuous energy
- tidal – the continual rise and fall of the tides can generate energy
- geothermal – drawing on the heat within the earth
- biomass – burning of biological material (wood, vegetable matter, etc) is a renewable energy source, but since it adds greenhouse gases to the atmosphere, it is not helpful in combatting climate change
Most of these renewable energies generate electricity, which can then be used in motor vehicles, heating and cooling, industry, etc. The technology of battery storage is improving all the time to allow electric cars to travel greater distances on a charge, and to allow energy to be stored during low use times and used in peak times and when less energy is being generated.
The cost of renewable energy is reducing all the time as new technologies are being developed. The cost of energy from solar and wind is now comparable with the cost of fossil-fuel powered energy, and likely to be a better financial investment than the development of coal mines and coal-fired power stations.
New agriculture methods
New technologies will hopefully allow the world’s food to be produced in ways that reduce greenhouse gases. Changes in diet (less meat intensive), better food distribution and avoiding food wastage may all play minor roles.
About a third of the carbon dioxide produced annually by burning fossil fuels is absorbed by forests. Re-growing forests on degraded land could help reduce atmospheric carbon dioxide, and also provide jobs and increase habitat for biodiversity.
Use less animal products, especially in food
Livestock makes up 94% of the total global biomass of non-human animals, they consume more food than they produce, and they add a significant amount of greenhouse gases to the atmosphere. If we all ate a lot less meat, especially red meat, greenhouse gases would be reduced and there would be more food to go round as the world population rises.
We have seen that growing more trees will take carbon dioxide out of the atmosphere. Techniques are also being developed to artificially store carbon rather than allow it to enter the atmosphere.
You and I can …
There are some actions we can all take – buy green power (maybe change energy providers to do this), eat less meat, pay carbon offsets when we travel by plane, use more energy efficient transport (e.g. electric or hybrid cars) and use less energy at home (avoid air conditioners and buy energy efficient appliances).
But the most important response we can make is to support political action to provide incentives for more efficient energy generation, transport, industry, mining and agriculture by being willing to pay more for goods and services.
The bottom line
As I outline on the next page, the costs of addressing climate change are significantly less than the costs of inaction. Whatever happens, our cost of living will increase slightly – either by taking remedial action now, protecting our planet and the lives of millions of people, or by continuing to vacillate, condemning millions of people to disaster and paying the inevitable cost of the problems which climate change will bring.
There’s no real choice, is there?
- NASA: Global Climate Change Causes
- Greenhouse gas emission data from Our World in Data and US EPA.
- NSW Department of Primary Industries Causes of Climate Change
- Renewable energy (US Energy Information Administration) and its costs (Forbes).
- Climate change and health (World Health Organisation).
- Economics of addressing climate change by Our World in Data and the London School of Economics and Political Science.
- The economic and human impacts as assessed by the World Bank.
- Things we all can do, by Australia’s Climate Council and the David Suzuki Foundation.
- Wikipedia Scientific opinion on climate change, Individual and political action on climate change, Individual action on climate change and Carbon sequestration.
Next: The cost of climate action.