Even halving our emissions won’t be enough. Here’s why
The Australian Government likes to claim we are doing our part to avoid dangerous climate change. Australia’s current target is to reduce greenhouse gas emissions by 5 to 25 per cent by 2020, compared to 2000 emissions levels, with a 60 per cent drop by 2050.
This sounds impressive enough, and there is no doubt that this will require transformative changes in energy use if it is to be achieved. Other developed countries have similar targets. President Obama’s aim for the USA, for instance, is to get back to 1990 levels by 2020 and 80 per cent lower by 2050.
So we’re doing our bit. But is this bit enough, or fair, or feasible? In short, no, no and no. Let me explain.
The problem with our emissions reduction target boils down to historical and current inequities. Consider the year 2000 baseline that is Australia’s carbon policy yardstick. In that year, human-caused carbon dioxide (CO2) emissions were about 34 billion tonnes globally. That’s a huge number, but it’s not so hard to put into context. For a world population of 6.5 billion people, it’s a little over 5 tonnes ‘er capita – that is, for each and every man, woman and child on the planet.
Australia’s per captia emissions, by contrast, are about 25 tonnes, which is about the same as the US, half that of the UK, and a third that of France. As you can imagine, the developing world’s average is much lower – about 4 tonnes for China, 2 tonnes for India and a measly 1 tonne for Bangladesh.
Now, in a recent issue of the science journal Nature, the useful idea of total global carbon budgets was presented. The startling bottom line of this published analysis was that if we wish to avoid the most dangerous consequences of climate change and limit total global warming to less than 2 degrees Celsius, we can only afford to burn between a third and a half of all the remaining coal, oil and gas reserves, between now and eternity (well, the next million years or so).
By the way, 2°C of warming is still bad, will require strong adaptive measures within our society and will still likely result in a whole lot of species extinctions and significant sea level rise.
Even worse, to have a decent (greater than three out of four) chance of avoiding 2°C warming, we must not emit more than 700 billion tonnes of CO2 between now and the year 2050. Yet, at our current yearly rate, we’ll have exceeded that number in just 20 years.
It turns out that if humanity can really get its act together an have global greenhouse gas emissions peak by 2015 and then decline at 4 per cent each and every year thereafter, then we have a reasonable shot at staying within 2°C. Under such a scenario, global emissions will have dropped by about 60 per cent by 2050 which is almost spot on the current Australian target.
But there’s a catch. It means the global average, for each man, woman and child, will be about one and half a tonnes of CO2 per year, because the United Nations expects the human population size to have increased to over 9 billion people by 2050.
Remember what Australia’s per capita emissions were in 2000? They were 25 tonnes each. So to meet a global target of a 60 per cent reduction by 2050, we’ll have to cut back by a whopping 94 per cent.
This, of course, presumes that a global climate agreement emerges from the principle of shared and differentiated responsibility, often called a “contraction-and-convergence” (C&C) approach. Although I acknowledge that a C&C agreement is highly unlikely in its purest form, I still suspect that if we are to achieve effective global reductions in greenhouse gas emissions, it will be on the basis of some agreement that is closer to C&C than anything resembling a full retention of historical advantages – which is what the current Australian policy implicitly assumes.
The bottom line: Australia’s target of 60 per cent reduction by 2050 is not supportable on the basis of climate science, and should be rejected. Current policy will break the world’s carbon budget.
A reduction of around 95 per cent by 2050 implies a near total decarbonisation of our electricity, construction, manufacturing and commercial sectors and transportation system, and a huge reduction in our agricultural sector.
I’ve no illusions about how tough this will be to achieve. But even so, let’s at least be completely honest about facing up to both the greenhouse targets required, if we are going to get really serious about the means required to achieve them.
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