While many of us will have enjoyed warm, dry weather, farmers in the south of the country will be concerned at the lack of winter rain for their crops. Winter is the dominant season for rainfall, especially in the southwest of the continent, so a return to wetter conditions would be welcome.
To deduce whether climate change had an influence on this particular event, I used two sets of climate model simulations: one representing the world of today and another representing a world without human influences (that is, with pre-industrial greenhouse gas concentrations).
I compared the likelihood and magnitude of dry Junes in the two sets of simulations to determine the net effect of human-caused climate change.
I looked at the climate change influence on very dry Junes (such as the one we’ve just experienced) both for Australia as a whole, and for the southeast, which had its driest June on record. Both of these areas received well below half of their average June rainfall in June 2017.
For Australia-wide June rainfall, I found a clear climate change signal towards drier conditions.
According to my analysis, climate change has increased the likelihood of very dry Junes by at least a third. The driest Junes now are about 12% drier than they would be in the absence of human greenhouse emissions.
When I looked at southeast Australia, however, I found that the influence of climate change is less clear.
My analysis suggested that climate change has probably increased the chance of dry conditions, although there is more uncertainty than for Australia as a whole.
That said, the driest Junes appear to be drier in the world of today than they would have been without climate change, by about 8% in the case of southeast Australia.
It’s not surprising that the result for southeast Australia is less distinct. Generally speaking, the smaller the area, the harder it is to detect an influence of climate change, as there is more year-to-year variability.
Under either a 1.5℃ or 2℃ global warming target, I project that dry Junes in Australia will become more frequent. For the southeast of the continent the picture is less clear, with high uncertainty in the change we might see.
The trend towards drier Junes across Australia is related to the southward shift in the storm track, the prevailing westerly winds that bring frontal weather systems across southern Australia. June 2017 is a very clear example of this effect.
Scientists use the Southern Annular Mode (SAM) to describe the position of the storm track. It has been trending towards more “positive” conditions, reflecting a poleward movement in the frontal systems which typically causes them to pass to the south of the Australian landmass.
These positive SAM phases bring drier conditions to most of Australia, but wetter conditions to coastal New South Wales. This is precisely what we have seen in June 2017.
As the effects of climate change intensify in the coming years, scientists expect to see the frontal systems that bring vital rainfall to the south of Australia moving further and further south. This increases the chance of Australia experiencing more dry Junes like the one just passed. Increasing temperatures will cause greater evaporation when there is rainfall, further exacerbating drought conditions.
You can find full details of the methods used in this analysis here.
The NCCARF received A$50 million in 2008 to coordinate Australia’s national research effort into climate adaptation measures. That was reduced in 2014 to just under A$9 million. For 2017-18, a mere A$600,000 will be spread between CSIRO and NCCARF to support existing online platforms only. From 2018, funding is axed entirely.
This decision follows on from the 2014 streamlining of CSIRO’s Climate Adaptation Flagship, and comes at a time when a national review of Australia’s climate policies is still underway.
Despite a growing global impetus to address the risks of climate change, there is evidence that Australia is being hampered by policy inertia. A review of 79 submissions to the Productivity Commission’s inquiry on Barriers to Effective Climate Change Adaptation, published in 2014, found that:
adaptation first and foremost requires clear governance, and appropriate policy and legislation to implement change.
Earlier this year the World Economic Forum listed “failure of climate change mitigation and adaptation” as one of the top five risks to the world, in terms of its potential impact. Meanwhile, in Australia, local governments, professionals and community groups have consistently called for more national policy guidance on how best to adapt to climate risks.
The government’s decision to slash funding for climate adaptation research is therefore at odds with the growing urgency of the problem. The Intergovernmental Panel on Climate Change, in its most recent major assessment report, pointed out that Australia can benefit significantly from taking adaptation action in highly vulnerable sectors.
These areas of vulnerability include: the risk of more frequent and intense floods; water shortages in southern regions; deaths and infrastructure damage caused by heatwaves; bushfires; and impacts on low-lying coastal communities.
To put it simply, lives and money will be saved by strong climate adaptation measures.
Like it or not, the federal government has to take a leading role in climate adaptation. This includes the ongoing need to address existing knowledge gaps through well-funded research.
The federal government is the major funder of leading research in Australia, delivered through CSIRO, the National Health and Medical Research Council, the Cooperative Reserach Centres, the Australian Research Council and universities. This role should not be divested. Without climate adaptation research, Australia can expect significantly higher infrastructure damage and repair costs, more death and disease, and more frequent disruption to services – much of which would be avoidable with the right knowledge and preparation.
In response to these known risks, there is demand for robust policy guidance. Effective partnerships between government, industry and the community are crucial. One such example led by the NCCARF is CoastAdapt, an online tool that collates details of climate risks and potential costs in coastal areas.
For projects like this, success hinges on full engagement with all relevant spheres of government, industry, research, and the community. There is more to be done, and it needs leadership at the highest level.
Australia’s summer is officially over, and it’s certainly been a weird one. The centre and east of the continent have had severe heat with many temperature records falling, particularly in New South Wales and Queensland.
For much of the country, the heat peaked on the weekend of February 11-12, when many places hit the high 40s. That heatwave, which mainly affected NSW, was quickly attributed to climate change. But can we say whether the whole summer bore the fingerprint of human-induced climate change?
The NSW record average summer temperatures can indeed be linked directly to climate change. We have reached this conclusion using two separate methods of analysis.
First, using coupled model simulations from a paper led by climatologist Sophie Lewis, we see that the extreme heat over the season is at least 50 times more likely in the current climate compared to a modelled world without human influences.
We also carried out an analysis based on current and past observations (similar to previous analyses used for record heat in the Arctic in 2016 and central England in 2014), comparing the likelihood of this record in today’s climate with the likelihood of it happening in the climate of 1910 (the beginning of reliable weather observations).
Again, we found at least a 50-fold increase in the likelihood of this hot summer due to the influence of human factors on the climate.
It is clear that human-induced climate change is greatly increasing the likelihood of record hot summers in NSW and Australia as a whole.
When we look at record summer heat, as represented by average maximum temperatures, we again find a clear human fingerprint on the NSW record.
The Sydney and Canberra heat
So what about when we dig down to the local scale and look at those severe heatwaves? Can we still see the hand of climate change in those events?
As climate varies more on local scales than it does across an entire state like NSW, it can be harder to pick out the effect of climate change from the noise of the weather. On the other hand, it is the local temperature that people feel and is perhaps most meaningful.
In Canberra, we saw extreme heat with temperatures hitting 36℃ on February 9 and then topping 40℃ for the following two days. For that heatwave, we looked at the role of climate change, again by using the Weather@home model and by comparing past and present weather observations.
Both of these methods show that climate change has increased the likelihood of this kind of bout of extreme heat. The Weather@home results point to at least a 50% increase in the likelihood of this kind of heatwave.
For Sydney, which also had extreme temperatures, especially in the western suburbs, the effect of climate change on this heatwave is less clear. The observations show that it is likely that climate change increased the probability of such a heatwave occurring. The model shows the same, but the high year-to-year variability makes identifying the human influence more difficult at this location.
A sign of things to come?
We are seeing more frequent and intense heatwaves across Australia as the climate warms. While the characteristics of these weather events vary a great deal from year to year, the recent heat over eastern Australia has been exceptional. These trends are projected to continue in the coming decades, meaning that the climate change signal in these events will strengthen as conditions diverge further from historical averages.
Traditionally, Sydney’s central business district has had about three days a year above 35℃, averaged over the period 1981-2010. Over the decades from 2021 to 2040 we expect that number to average four a year instead.
To put this summer into context, we have seen a record 11 days hitting the 35℃ mark in Sydney.
It is a similar story for Canberra, where days above 35℃ tend to be more common (seven per year on average for 1981-2010) and are projected to increase to 12 per year for 2021-40. This summer, Canberra had 18 days above 35℃.
All of these results point to problems in the future as climate change causes heatwaves like this summer’s to become more common. This has many implications, not least for our health as many of us struggle to cope with the effects of excessive heat.
Some of our more unusual records
While the east battled record-breaking heat, the west battled extreme weather of a very different sort. Widespread heavy rains on February 9-11 caused flooding in parts of Western Australia. And on February 9 Perth experienced its coldest February day on record, peaking at just 17.4℃.
Back east, and just over a week after the extreme heat in Canberra, the capital’s airport experienced its coldest February morning on record (albeit after a weather station move in 2008). Temperatures dipped below 3℃ on the morning of February 21.
The past few months have given us more than our fair share of newsworthy weather. But the standout event has been the persistent and extreme heat in parts of eastern Australia – and that’s something we’re set to see plenty more of in the years to come.
If you thought the climate debate has been ugly, you haven’t seen anything yet. In 2017 Australia will review its climate policies, and the process is not off to a good start.
To recap: with the release of the climate review’s terms of reference at the end of 2016, the federal environment and energy minister, Josh Frydenberg, appeared to place on the table an emissions intensity scheme (a widely supported form of carbon pricing). He then wisely went to Antarctica.
In the same week, Chief Scientist Alan Finkel reported his initial findings on the security of the National Electricity Market. He stated that his review “will continue to analyse all the options to ensure future security of power supply and compliance with climate obligations”.
And that was only 2016…
The Finkel review of the National Electricity Market will be released in 2017. At the same time, the government will begin its climate policy review.
Unless the political circumstances change dramatically, the review will conclude by the end of this year.
Every step of the way will see protests, media stunts, hostile leaking and lobbying – public and private – by big actors. Climate and energy will consume the national news agenda, which will leave voters and viewers exhausted.
regulating the closure of coal-fired power stations – this seems unlikely too, given the failure of the “cash for closures” scheme under the Gillard Labor government
further restrictions on land use (unlikely to make the National Party very happy) and research into methane reductions from livestock (cue headlines about cow farts).
But asides from not making environmentalists particularly happy, these will not resolve the questions of grid security and energy pricing, both of which have the potential to cause political and economic mayhem.
Sharpen the pitchforks
Labor will use climate as a “wedge issue”, perhaps more gingerly and cautiously than Kevin Rudd did ahead of the 2007 election.
However, Weatherill may now be tempted to deflect blame for any South Australian energy problems onto Turnbull, who has made himself into a piñata.
Business is fuming and some odd coalitions are forming. The policy uncertainty (caused of course in no small part by the business sector’s failure to defend Gillard’s carbon tax) is aggravating them and scaring away investment. The worst possible outcome for business – a patchwork of state laws causing more work and less profit – is a distinct possibility.
Expect to see a “gas versus coal” battle, with coal pointing to gas prices rising, because it fetches more on the international market. The question of reservation policy – hated by many – may attract some strange allies.
The environmental movement will struggle over this. They are still bruised over the Rudd and Gillard policy battles, and an emissions intensity scheme is numbingly technical. In her excellent PhD thesis at the University of New South Wales, Rebecca Pearse argued that many activists have moved on to either supporting community-based renewables or contesting fossil-fuel infrastructure projects.
Of course, anti-green groups will also be hard at work, perhaps led by Coalition MPs Cory Bernardi and George Christensen and the Institute of Public Affairs. All have argued that Australia should do much less on climate change.
Finkel’s final electricity review is due in March. It will be interesting to see if the attacks that have happened to other scientists involved in climate and energy happen to him.
At some point in 2017 Al Gore will release a sequel to his 2006 documentary An Inconvenient Truth. Expect to see reactions to that.
Will President Trump have taken the United States out of the Paris Agreement by then? Will the US pull out of the entire climate convention? Or will Trump settle for just sending the office junior to the negotiations, while gutting his Environmental Protection Authority?
Nobody knows, probably not even the president-elect himself. A recent ANU study points to Trump-style disaffection taking hold in Australian politics.
There’s a hoary old Machiavelli quote that gets dragged out in articles like these about the political pain that transitions cause:
It ought to be remembered that there is nothing more difficult to take in hand, more perilous to conduct, or more uncertain in its success, than to take the lead in the introduction of a new order of things.
In these dire times, it is unclear who could call an end – or a ceasefire – to what Guardian journalist Lenore Taylor calls “the stupid barren years of the carbon wars”. It’s what some public policy theorists call a “hurting stalemate”.
After a disappointing 2016, when most of the annual major meteor showers were washed out by moonlight, 2017 looks far more promising.
Of the big three, the Quadrantids in January and Geminids in December are both visible in dark, moonless skies. Sadly, the Perseids in August will again be badly obscured by a waning gibbous Moon, but they are always worth watching.
Here we detail the predicted meteoric highlights for the coming year for the northern (N) and southern (S) hemispheres, and those visible for both (N/S).
New this year, for each shower we also give the maximum Zenithal Hourly Rate (ZHR): the maximum number of meteors per hour that could be seen, given absolutely ideal conditions.
The rates you actually observe will be lower than this value. The higher a shower’s radiant in the sky, and the darker the conditions, the closer the observed rates will get to the ZHR.
For each shower, the time of forecast maximum is given in Universal Time (UT), with conversions to local time for certain regions where the shower could be observed. For other regions simply convert from UT into your local timezone.
The parent is the comet or asteroid responsible for the debris through which the Earth passes each year that’s the cause of the annual meteor shower.
Active: December 28, 2016 – January 12, 2017
Forecast Maximum: January 3, 2pm UT = January 3, 6am PST (West Coast, US) = January 3, 11pm JST (Japan)
The Quadrantids get the new year off to a meteoric start. At their peak they can be spectacular, with rates often exceeding 100 meteors per hour.
For locations north of 40 degrees north, the shower’s radiant (the point on the sky from which the meteors appear) is circumpolar, which means it is always above the horizon.
The result? Quadrantid meteors can be seen throughout the hours of darkness. The best viewing is after midnight, local time, as the radiant climbs high into the morning sky.
For most of the shower’s fortnight of activity, only one or two meteors per hour might be seen. For that reason, the Quadrantids are often overlooked, but at their best, they are well worth the effort of setting an early morning alarm on a cold winter’s night.
The forecast maximum this year favours locations in the western part of North America and in far East Asia. Observers north of the Arctic Circle have the privilege of being able to watch the shower continuously, if they can brave the winter cold.
Active: April, 16-25
Forecast Maximum: April 22, 12pm UT = April 22, 5am PDT (West Coast, US) = April 22, 10pm AEST (QLD/NSW/ACT/Vic/Tas) = April 22, 8pm AWST (WA)
The Lyrids are a fairly consistent, moderately active meteor shower, producing around 15 to 20 meteors per hour at their peak.
Visible from either hemisphere, the Lyrids are best observed from northern latitudes, where the radiant climbs high in the sky before dawn. This year, the forecast peak favours observers in the Americas, although the precise timing of the maximum has been known to vary somewhat from year to year.
The Lyrids have the longest recorded history of any meteor shower, with observations dating back to at least 687BC.
While the Lyrids are typically only a moderately active shower, they can occasionally be truly spectacular. Every 60 years or so, they produce rates much higher than normal, an event known as an outburst.
The most recent such event occurred in 1982 when, for a short time, rates topped 90 meteors per hour. In 1803 the shower was more spectacular still. Rates reached storm proportions, and the sky over the eastern states of the US was alight with meteors, rates of more than 700 per hour.
This year, unfortunately, no such enhanced activity is forecast. Nevertheless, the Lyrids are still worth a look, letting us see pieces of a comet that currently lies more than a hundred billion kilometres distant.
Eta Aquariids [S]
Active: April 19 – May 28
Forecast Maximum: May 6, 2am UT = May 6, 12pm AEST (QLD/NSW/ACT/Vic/Tas) = May 6, 10am AWST (WA)
For observers in the southern hemisphere, the Eta Aquariids are one of the highlights of the meteor calendar.
Active in autumn, as the nights grow ever longer, the Eta Aquariids are best observed in the hours before dawn, when rates can climb as high as 40 or 50 meteors per hour.
Even for locations well south of the equator, the radiant does not rise until 1am or later, so this is definitely one to set the alarm for.
The Eta Aquariids are the stronger of two annual showers produced when Earth passes through debris shed by Comet 1P/Halley. We’ll come to its sister shower, the Orionids, later.
The debris shed by Comet Halley is spread in a wide band across Earth’s orbit, which results in the Eta Aquariids being active for a period of around six weeks. Peak rates occur for just a week or so around the forecast maximum.
Observers who brave the pre-dawn hours to observe the shower this year are in for an added treat, with Venus and Mercury putting on a spectacular show as the dawn twilight builds.
The Eta Aquariids themselves are fast meteors, and are often bright, continuing to make an impression as the sky brightens before dawn.
The Southern Delta Aquariids, Piscis Austrinids and Alpha Capricornids [N/S; S favoured]
During late July and early August, three meteor showers combine to provide a nice spectacle for keen observers, particularly those in the southern hemisphere.
Given that the normally reliable and spectacular Perseids (mid August) are badly affected by moonlight this year, these showers allow observers to get their mid-year meteor fix.
These three showers, combined, favour observers in the southern hemisphere, though they can also be observed from northern latitudes. From both hemispheres the rates get better as the night goes on and the radiants rise, with the best rates seen in the hours after midnight.
Of the three, the Southern Delta Aquariids are the most active, with a broad peak lasting around five days, centred on July 30. Their meteors are the fastest of the three showers, as well as the most numerous.
The Alpha Capricornids, by contrast, are relatively slow and infrequent (just five or so per hour), but are often spectacular, with a reputation as a fireball shower. When combined with the activity from the other two showers, they represent a great opportunity for budding astro-photographers to get some spectacular shots.
The Orionids are the second of the annual meteor showers associated with the most famous comet, 1P/Halley.
In October, the Earth passes slightly farther from the densest part of Halley’s debris stream than in May, so the Orionids are somewhat weaker than their sister shower.
This is more than offset by the ease with which they may be observed. The Orionid radiant reaches a reasonable altitude by around midnight, local time. As a result, the shower can yield good rates for several hours before the sky starts to brighten before dawn.
Though peak rates are forecast to occur on October 21, the Orionid maximum is usually a broad and prolonged affair. Good rates can be seen for several days before and after the maximum, with several sub-maxima occurring as Earth passes through denser filaments of debris in the broader stream.
Orionid rates are supplemented by meteors from the Taurid stream, a minor shower active from September until December. Where the Orionids are fast, the Taurids are very slow but they often produce spectacular fireballs.
Active: December 4-1
Forecast Maximum: December 14, 6:30am UT = December 14, 1:30am EST (East Coast, US) = December 14, 5:30pm AEDT (NSW/ACT/Vic/Tas) = December 14, 4:30pm AEST (QLD) = December 14, 2:30pm AWST (WA)
The Ursids are the final shower of the year, and are only visible for locations in the northern hemisphere.
Ursid meteors radiate from within just 14 degrees of the north celestial pole, so the radiant only changes in altitude by 28 degrees over the course of a night!
In most years, the Ursids are a fairly minor shower, yielding only ten meteors per hour at their peak for dedicated observers. But in the past they have produced at least two major outbursts, and the maximum activity seems to vary somewhat from year to year.
No major outburst is forecast for this year, but the Ursids are a shower of surprises.
There is the possibility that the Earth will encounter a denser clump of debris around 15 minutes ahead of the time of forecast maximum. That debris, left behind by the shower’s parent comet, 8P/Tuttle, in 884AD, will likely have become quite dispersed in the 1,133 years since it was lain down. As a result, any increase to the observed rates will probably be relatively small.
But it could still be well worth a look, just in case the Ursids manage to surprise us once again.