Time to stop waffling about degrees of climate danger

"Erratic", "inconsistent", "highly political" and "lacking in direction". That's the unvarnished verdict on Australia's climate policy, according to experts within our own Parliament House.

It wasn't a statement from the government or even the opposition. Instead, it came from the well-respected Parliamentary Library, which this week quietly released a helpful timeline of Australian climate change policy since the 1970s.

By chance, that timeline came out just ahead of an important new paper by a team of global experts, and a new book here in Australia.

Both highlight how little the world has done to tackle climate change in all that time. But they also point to some clear solutions that could help us avoid a dangerously hot future, including: tougher emissions targets, putting a price on carbon emissions, rapidly reducing our reliance on fossil fuels, and - in Australia's case - ending its insupportable boom in coal and gas exports.

Two degrees is one too many

It is time to stop waffling so much and say that the evidence is pretty strong that the greenhouse effect is here. - NASA scientist Dr James Hansen, June 1988.

Twenty-five years ago James Hansen warned a US Congress hearing that global warming was a problem they could no longer afford to ignore.

His latest research, published yesterday, warns that the widely-supported international target of stopping the average global temperature from rising to 2 degrees Celsius (3.6F) above the pre-industrial level would have "disastrous consequences".

Co-written with a high-profile global team including US economist Jeffrey Sachs and Australian coral expert Ove Hoegh-Guldberg, their Assessing Dangerous Climate Change paper finds:

some climate extremes are already increasing in response to warming of several tenths of a degree in recent decades. These extremes would likely be much enhanced with warming of 2°C or more.

Critically, the authors argue that it would be "exceedingly difficult… yet still conceivable" to limit human-induced warming to about 1°C (1.8°F) with strong action.

They support a carbon tax, which they say is simpler and easier than an international emissions trading scheme; greater investment in technology development; and cutting energy subsidies, including "large direct and indirect subsidies" for fossil fuels.

But to achieve their aim of about 1°C of warming, current global emissions would need to be cut by 6% per year starting from this year - when in fact, emissions are continuing to rise.

Extreme risks for Australia

Based on existing emissions trends and insufficient national mitigation pledges, we're actually on track to see average global warming of around 4°C by the end of this century, if not earlier.

Released last night, the book Four Degrees of Global Warming: Australia in a Hot World - of which I am the editor - reports the latest research on what 4°C of warming would do to Australia's environment, society and economy.

Given current trends, by the end of this century Australia will be a continent under assault: hotter, subject to greater extremes of weather such as bushfires, floods, storms, droughts, possibly hungrier, poorer and more insecure.

For instance, increasing temperature and declining rainfall could undermine agricultural production. By the end of the century, Australia could go from exporting its surplus food to struggling to feed its larger domestic population.

Other significant contributors to Australia's economy - tourism, fisheries and mining - would be substantially transformed and severely affected.

A 4°C world would batter Australia's environment. Extreme events and rising temperatures would force more Australian species to extinction. The Great Barrier Reef would be devastated by gradual warming, high-heat bleaching events, and ocean acidification. The A$6.4 billion tourism industry it supports would likely collapse.

Pressures on the national economy would be compounded as governments and communities struggle to deal with the rising costs of adaptation and remediation in the face of extreme events. Basic services like public transport and housing, water, sewerage, health and communications would be under increasing stress.

By the end of the century living in Melbourne could become climatically like living in southern NSW, Sydney like Rockhampton, and Alice Springs like the Sudan. In Darwin, the number of days over 35°C is projected to rise from an average of 10 a year now to more than 300 - which would be like nowhere on Earth today.

What we can do

Assessed against these threats and their costs to Australian communities and ecosystems, the weakness of current policies and targets becomes starkly evident.

To avoid this scenario, Australia - as well as other countries, particularly those that contributed the most cumulative emissions over the years (see charts below) - must dramatically step up its efforts in this critical decade.

We have to change our emissions reduction target, from aiming to cut emissions 5% below 2000 levels by 2020 to, at minimum, aiming for a 38% reduction by 2020.

That target is appropriate given what climate science is telling us: it's the necessary contribution Australia has to make to bridging the emissions gap between a 4°C world and a path to warming closer to 1.5°C.

Leading economists such as Nicholas Stern and Ross Garnaut agree that early and effective action will be less expensive and more effective than delay. If countries like Australia stopped being so erratic on climate policy, and finally committed to long-term, serious emissions reductions, we would be providing the international leadership needed to start making the "exceedingly difficult… yet still conceivable" changes proposed by Hansen and his co-authors.

No regrets

But the grounds for hope in Australia are presently thin; the political climate is, euphemistically, challenging.

As the Parliamentary Library's timeline reminds us, back in the 1980s Australia adopted a national target of cutting emissions 20% on 1988 levels by 2005 - but only as a "no regrets" strategy. The loophole was that any reduction would not be "at the expense of the economy".

Similar short-termism has largely won out in decades that followed - and it looks like it could prevail again with the Coalition government's push to repeal Australia's carbon price.

Australian efforts and international negotiations are increasingly at odds with the scientific evidence on the need for urgent, substantial emissions cuts.

Unless we can break from this pattern of political and policy neglect, Australia will reap a 4°C future. In what way is that a "no regrets" strategy?

Peter Christoff, Associate Professor, University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.