The link below is to an article reporting on the death of naturalist Harry Butler, an icon of the Australian bush.
Australia is the land of drought and flooding rains, and in a recent paper we’ve shown that’s been the case for more than 500 years. As part of our Australia and New Zealand Drought Atlas we’ve published the most detailed record of drought and wet periods (or “pluvials”) since 1500.
The data reveal that despite the severity of the Millennium Drought, the five worst single years of drought happened before 1900. But 2011 was the wettest year in our 513-year record.
The dominant theme of Australia’s drought history is variability. We may get one year of extremely wet conditions (for example in 2011) or we might get six years of extremely dry conditions (such as 2003-2009).
North Queensland may be flooded out while Victoria suffers with drought. Or in extreme circumstances, the entire eastern half of Australia might be bone dry.
Even as people change the climate by adding greenhouse gases to the atmosphere, variability will continue to play a large role in Australia’s climate. This year one of the strongest El Niños on record is kicking into high gear in the tropical Pacific, driving global temperatures higher still.
To tease out these complex patterns we need to look deep into the past.
It’s in the trees (and coral)
The existing drought records are relatively short and geographically patchy. Measurements from weather stations rarely extend beyond the early 1900s and informal historical records from diaries and ships logs — some of which go back to the first days of European settlement in Australia — are relatively uncommon and limited to a few sites. This has limited our understanding of drought variability to what has been directly observed over the past 120 years.
To extend the drought record beyond 1900, we used 177 tree ring and coral records from Australia, New Zealand, and Indonesia to reconstruct summer (spanning December to February) drought conditions in New Zealand and most of Australia.
Trees and corals are sensitive to their environments. For example, trees grow less in dry years and more in wet years. We carefully examined, dated, and measured each growth ring in thousands of trees and then compared the patterns of growth to an index of drought variability, the Palmer Drought Severity Index.
This index takes into account air temperature, rainfall, and soil water-holding capacity to give an indication of the water status of the environment. However, the data only extend back to 1900. By using the statistical relationship between drought and our tree rings and coral, we can translate the growth patterns into data going back hundreds of years.
What we found was a remarkably rich and complex history of wet and dry conditions, particularly across eastern Australia.
A history of drought
Over the past five centuries we found extreme droughts similar to the recent Millennium Drought, but we also discovered wet periods that lasted decades.
We found short droughts of brutal intensity that blanketed all of eastern Australia, while other droughts of similar intensity were confined to small pockets across the continent.
The atlas also provides new geographical context for early historical droughts. For example, diaries from early settlers near Sydney documented a crippling drought in 1791-92. Our data demonstrate that this was one of the worst drought years in the past 500 years with extraordinarily dry conditions that stretched from Cape York to eastern Tasmania. The early colony was fortunate to survive.
An obvious question is how do our modern droughts and floods stack up against earlier events? Of the five most extreme single years of drought in the past 500 years (when averaged across all of eastern Australia), not one occurred after 1900.
In contrast, two of the five wettest years in our data took place after 1950 (2011 was the wettest year in the 513-year record). The 1700s were particularly dry with three of the five worst drought years, but also notably had the most prolonged wet period (1730-60).
In eastern Australia, wet and dry conditions cycle back and forth over several decades, driven by the oceans around us.
When we compared the data to a recently developed index of changing atmospheric pressure called the Interdecadal Pacific Oscillation (IPO), we found remarkable consistency between the two. The IPO tells us when we have unexpectedly warmer or cooler sea surface temps and air pressures. The IPO also interacts with El Nino and La Nina to make them stronger or weaker.
When the IPO was positive, eastern Australia experienced drought conditions for several decades; when it was negative, eastern Australia experienced pervasive wet conditions. From 1999-2012 we were in a negative phase of the IPO; now it appears we have just entered a strongly positive phase.
You may have noticed that the Millennium Drought happened in a negative IPO phase. Our data show that there is a strong relationship between the phases of the IPO and drought – until around 1976. After that the relationship gets weaker. Why is a question for further research, but one possibility is human-caused climate change.
This new data will help us understand what drives these swings between drought and floods, and help us predict what might happen in the future.
Patrick Baker, ARC Future Fellow and Associate Professor of Silviculture and Forest Ecology, University of Melbourne; Chris Turney, ARC Laureate Fellow and Professor of Earth Sciences and Climate Change, UNSW Australia, and Jonathan Palmer, Research Fellow, Climate Change Research Centre, UNSW Australia
How should we react to the likely outcome of the Paris climate conference? Unless something dramatic happens overnight it is very likely that the news media on Sunday morning will hail the Paris agreement as a breakthrough and a big victory for those pushing for strong action on carbon emissions.
Yet on Friday we heard from some of the best-informed scientists that the outcome will be a catastrophe.
So who is right? They both are. It depends on the question being asked.
One question is: “What could we reasonably hope would be achieved at the Paris conference?” In my assessment (that is, compared to my expectations about what was possible based on experience and the signs coming into the conference), the likely agreement is about as good as could be hoped for.
It finally acknowledges that warming should be kept below 1.5°C, there will be five-yearly reviews (with exceptions), climate financing has been ramped up, the crippling formal division between rich and poor countries has been broken down and various other provisions have been resolved towards the good end of expectations.
It’s become clear that what is being achieved in the negotiating rooms is being trumped by what is happening outside. In the last fortnight I have witnessed the quite amazing shift among investors and “non-state actors” that signals a sea-change in climate action that now seems unstoppable. (This comes from someone with a well-founded reputation as a doomsayer).
But there is another question that can be asked: “Will the Paris Agreement be based firmly on the science and commit the parties to actions that will limit global warming to less than 2°C and preferably 1.5°C?” The answer to that is undoubtedly no.
The country commitments brought to Paris are expected to limit warming to perhaps 3°C, which will be catastrophic if it occurs. Limiting warming to 1.5°C now seems impossible. As Steffen Kallbekken, Research Director at the Centre for International Climate and Energy Policy, put it at a conference briefing: by the time the current pledges enter into force in 2020, we will probably have exhausted the entire carbon budget for the 1.5°C degrees target.
So the Paris agreement arguably locks us into a warming trajectory that will be disastrous.
Worse than Copenhagen?
How are we to find our way through these conflicting stories?
Consider the statement on Friday by Kevin Anderson. He made the heart-stopping claim that the deal as it stands is worse than the Copenhagen Accord. The commitment to science has been stripped out in Paris, he said, and emissions from shipping and aviation, huge and growing sources of emissions, have now been “exempted”.
Anderson knows carbon budgets better than most; but if we stand back and look at the effect of the Copenhagen agreement on the world versus the likely effect of the Paris agreement on the world then his claim makes no sense.
When the media, and everyone else, declared that Copenhagen was a disaster the signal to the world, and especially to business, was that nations cannot agree and not much is going to happen.
Yet when the media, and almost everyone else, reports that Paris was a huge success the signal to the world, and especially business, is that nations have agreed on a firm direction, that the world is rapidly changing and that you are crazy if you do not get on board.
Two right answers
There is good reason to feel, like me, torn in two directions. For those who understand the situation, the polarity sets up a powerful tension. If it’s uncomfortable to be suspended between the poles, it’s dangerous to go all the way to one or the other.
If we allow ourselves to be drawn over to the everything-will-be-OK pole, we are ignoring the science and indulging in wishful thinking.
If we allow ourselves to be drawn over to the catastrophe pole, which is quite consistent with the science, then we become unable to recognise and encourage the positive steps that are being made. Three degrees is a big improvement on four, and 2.5°C is even better, even if it remains bad. But what matters most is momentum.
After writing the “good news” stories I mentioned, hearing the scientists again was like a bucket of cold water. But we have to live between the poles, because it is the tension that allows us to believe that the great step forward of Paris, while still a long way short of what is needed, could set the world on a path where much more becomes possible.
Clive Hamilton, Professor of Public Ethics, Centre For Applied Philosophy & Public Ethics (CAPPE)
The UN climate summit is due to reach an agreement on Saturday afternoon, Paris time. By this stage of the ill-fated Copenhagen summit six years ago, the wheels were already coming off. People had started to panic. The grand dream – laughably ambitious in retrospect – was evaporating.
Paris is different. The mood is fairly upbeat, and someone (French foreign minister Laurent Fabius) is in charge. A solid deal which will help avoid dangerous global warming is within reach. The earnest, tired negotiators can almost taste it. They are working through the night – in fact several nights, because the summit will now run over – to land it.
A disaster of Copenhagen proportions is unlikely now. But nor is it possible that the summit can clinch a deal to cap global warming at 2℃, or 1.5℃ (both targets are featured in the latest draft text, released late on Thursday evening). There’s one thing all 196 countries at these talks do agree on, and that’s that they’re not yet ready to commit themselves to the deep national cuts in greenhouse gas emissions that scientists say are required. Climate change always has been someone else’s problem.
At this point I could talk about UN processes, about texts and brackets and articles, but I’ll spare you the full horrors of the UN bureaucracy.
The two most likely options are: first, a fairly strong deal which charts a course towards avoiding dangerous levels of global warming. The idea is that deal would be ratcheted up over time. It would cement quite strong ambition on addressing climate change, with more hard work to come.
Option B is a weaker deal which settles for more modest ambition. It would let countries off the hook on their emissions, and it would not feasibly map out a course to keep global warming to 2℃ or 1.5℃. Option B would not be without value; it would help lay out some of the global architecture to reduce emissions and it would be more ambitious than what came before. But it would confirm what many already suspect – that the UN cannot solve climate change. Under the UN system, 196 countries have to agree on every word of this deal. And those countries include oil producers, coal exporters, countries with parliaments loaded with climate sceptics, and desperately poor countries with more immediate problems to fix. Is it any wonder that 23 years of these summits have produced so little?
At this stage the issues that will determine whether the Paris deal ends up being option A or option B are how ambitious the deal is on cutting emissions and the language used on that; how the deal strikes a balance between developed and developing countries; and whether richer countries put enough money on the table to help poorer countries.
Plenty of people at the utilitarian Le Bourget conference centre in outer Paris will tell you which way the deal is heading, but the truth is at this stage no one knows – not even the leaders of the United States, China and India, who may make a decision over a phone call on Friday night or Saturday morning.
Wherever the Paris deal falls, however, it will only be part of the story on planet earth’s future climate. Sure, the media loves a big summit with celebrities (of whom there have been plenty here). But what’s becoming increasingly clear is that what matters is what’s done by federal, state and local governments, by businesses, by board members, by entrepreneurs, and by ordinary people from Beijing to Bhopal to Broome.
This post was originally published on the Melbourne Sustainable Society Institute’s COP21 blog.
There are hundreds and hundreds of side events across the two weeks of the UN climate conference here in Paris. It’s often hard to choose between them. Choosing to attend the International Civil Aviation Organisation (ICAO) side event on aircraft emissions on Wednesday evening was made easier by virtue of it being the only dedicated event dealing with such emissions at the whole conference.
Notwithstanding that, there’s also a significant UN conference next year at which (so it’s said) all states will agree to the parameters of a market-based mechanism – presumably an emissions trading scheme – to address the aviation emissions problem.
Aviation emissions are currently unregulated. ICAO is the UN agency tasked under the UNFCCC to deal with the aviation’s emissions problem. I almost wished I hadn’t gone to the aviation side event.
The flyer stated that the side event would “highlight ICAO’s expectations for COP21 and will provide concrete insights into ICAO’s successful strategy and initiatives to assist the development and implementation of states’ action plans to reduce aviation emissions”.
Further, the focus was on ICAO’s “achievements and joint initiatives with other UN bodies and the aviation industry on technical, operational and market-based measures”.
So I was forewarned.
In his introductory speech, Olumuyiwa Benard Aliu, President of the Council of ICAO, referred to ICAO’s “leadership in reducing [aviation] emissions” and its “tremendous efforts” in this regard, including the development of sustainable fuels and emissions reductions through improvements in air traffic management.
Subsequent speakers, including a representative from the Air Transport Action Group, referred to “successful efforts” to address the level of aviation emissions (remember that aviation emissions are largely unregulated and are increasing, in contrast with many other industry sectors) and the necessity of ICAO as the organisation through which the problem should be resolved.
References were also made to cooperation among a range of aviation entities in order to enable thousands of flights to operate on a daily basis – presumably some sort of reference to cooperation either (a) being at the ready to help address the emissions problem, or (b) already being utilised.
The problem is that ICAO has not addressed the aviation emissions problem – and this is what COP21 didn’t hear about (among other things). Note the following:
At ICAO’s triennial assembly in 2013, its member states agreed to proceed with a roadmap towards a decision to be taken in 2016 for implementation in 2020 – effectively, an agreement to agree, and nothing more.
Air travel continues to grow by up to 4-5% on a sustained basis each year.
If the aviation industry was a country, it would be ranked seventh in the world for carbon emissions, between Germany and South Korea.
According to UN estimates, total aviation emissions will be anywhere between 290% and 667% above 2006 levels by 2050, assuming no switch to alternative fuels.
Does that sound like “successful efforts” to address the level of aviation emissions?
Rebecca Johnston contributed reporting for this blog post.