Introducing Climate Change

The world (and Australia) is getting hotter

Average global surface temperatures have increased by about 1 degree C since the late 1880s.  This change is represented in the graphic at the top of this page. Climate change is not a future possibility, it is happening right now, and will continue to get worse.  How much worse depends on how quickly the nations and peoples of the world reduce their impact on the climate.

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It’s Caused by Human Activity

Climate change is caused by humans emitting greenhouse gases – primarily carbon dioxide and also methane, nitrous oxide and other gases – which increases the concentration of these gases in the atmosphere.  Because these gases absorb heat they trap this heat in the earth’s atmosphere,  causing it to become warmer.  The higher the concentration of these gases in the atmosphere, the warmer it will become.

 

These gases are emitted through a range of human activities, such as:

• Burning coal, oil or Liquified Natural Gas to generate electricity.

• Burning oil to power cars, trucks and planes.

• Clearing forests to make way for agriculture or urban development or for logging – there is a lot of carbon stored in trees and soil, and this is released into the atmosphere if they are cut down.

• Various industrial processes which emit carbon, such as steel and aluminium manufacture.

• Raising certain animals for meat – particularly cattle and sheep, which emit large quantities of methane in the process of digestion.

 

Climate Change Has Serious Impacts

Climate change is not just a matter of the earth getting warmer – the increased temperature changes a lot of other things too.  Impacts include:

• Rising sea levels as a result of melting ice in the Arctic and Antarctic.

• A more acidic ocean, with significant impacts on marine life.

• Changed rainfall patterns, with some places (like the southern half of Australia) getting drier, while others (including the northern half of Australia) get wetter.

• More frequent and/or more intense extreme weather events, including droughts, bushfires, heatwaves, floods and cyclones.

• Widespread species extinction as a result of changed climatic conditions.

 

These Impacts Cost Money

You will sometimes hear politicians say that they would like to take strong action on climate change but they don’t want to ruin the economy, as if we need to choose between the environment and the economy.  This is stupid.  Climate change is and will continue to be hugely costly.  Some of the most important costs include:

• Lost agricultural production as a result of changed rainfall patterns, especially drought.

• Increased property damage from flood, fire and storm, and the increased insurance premiums we all have to pay to insure against these risks.

• The loss of usable coastal land to rising seas.

• The loss of fisheries and damage to industries such as reef tourism as ocean acidification leads to loss of sea life.

• The costs to government and communities of adapting their infrastructure to make it more resilient.

 

It’s very hard to estimate how much this economic impact will be, and economists have come up with figures anywhere between 0.2% and 7% of global GDP by 2100 – that is, between US$0.2t and US$6t per year. 

 

We Can Limit Climate Change

The 2015 Paris Agreement saw the world’s nations agree to take action to limit global temperature increases to between 1.5 and 2 degrees C.  This requires us to move decisively to cut emission of greenhouse gases.  The good news is that it is highly feasible for us to do so.  Key strategies to make this happen include:

• Shifting electricity generation from fossil fuels (coal, oil, gas) to renewable sources of power (wind, solar, hydro-electric).

• Electrifying our transport systems through greater public transport, use of electric vehicles and greater use of active transport (walking, cycling, scootering etc).

• Shifting to non-emitting industrial processes – for instance using hydrogen instead of coking coal to make steel.

• Changing agricultural and land management practices to shift from livestock such as cattle which emit large amounts of methane to less emitting products, and changed practices around fertilizer and land clearing.

 

We already have the technology to make these changes and in many cases (for instance, in electricity generation) they are now less expensive than fossil fuels. 

 

The Paris Agreement has had a rocky start.  Many nations, including some of the biggest emitters like the USA and China, have yet to commit to big enough cuts to reach the goal.  President Trump withdrew the US from the agreement, although President-elect Biden will reverse this when he takes office.  Much of this slowness, including here in Australia, is driven by fierce lobbying from fossil fuel companies who see their business becoming rapidly obsolete.  Change is never easy, but in this case it is both possible and necessary.

 

Adaptation Will Be Needed

Even if we succeed in achieving the goals of the Paris agreement, we will still need to adapt to a changed climate.  We are already living with temperatures one degree hotter than the historical average, and it is now impossible to do better than the 1.5-2 degree target.  We saw the consequences of this in 2019-20 in the extensive drought and worst-ever bushfires. 

 

There are a number of aspects to climate adaptation.  For instance:

• Addressing sea level rises by either building sea walls and other protections against tidal incursions, or moving human settlements further from areas prone to increased inundation.

• Adapting agricultural practices to take account of changed rainfall patterns and higher temperatures.

• Adapting housing, commercial buildings and community infrastructure to take account of climatic changes.

 

In addition to this, as fossil fuel industries become unviable we will need to manage the economic transition to protect the workers and communities that have historically relied on these industries.  We need to replace coal mines and generators, gas drilling and transport industries with viable, long-term businesses and jobs based on renewable technologies.

 

Aspects of our lives and communities will inevitably change.  But change is not always bad, and we have an opportunity to make our communities and physical environments better in the process.

 

Climate Change Is Not Our Only Challenge

Climate change needs to be seen in the context of a wider set of ecological and social challenges.  When responding to climate change, we need to take account of a range of other factors:

• Pollution results in more than just climate change – it also creates a toxic environment in other ways, for instance plastic pollution and chemical pollution harming sea life, and air pollution making the air of many cities unbreathable.  Combating climate change can also help address some of these problems.

• Global inequality interacts with climate change in complex ways – poor communities and nations are more vulnerable to climate change than rich nations because they have less of a buffer.  At the same time, poor countries can find it hard to cut emissions while at the same time trying to increase economic wellbeing. 

• Resource depletion sits alongside climate change as a ‘hard limit’ on certain kinds of economic activity.  There is only so much coal, oil, iron ore and so on in the earth’s crust and eventually we will use it all up and need to find other materials.  At the same time, many industrial agricultural practices result in depletion of topsoil and groundwater, making these practices unsustainable in the medium term.  These limits mean that before too long we would have to change many of our technologies and practices even if there was no need to combat climate change.  Climate risk just makes us do it sooner.