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Donald Trump signed an executive order on Tuesday to undo a slew of Obama-era climate change regulations that his administration says is hobbling oil drillers and coalminers, a move environmental groups have vowed to take to court. The decree’s main target is Barack Obama’s clean power plan that required states to slash carbon emissions from power plants – a critical element in helping the United States meet its commitments to a global climate change accord reached by nearly 200 countries in Paris in 2015

• Trump moves to dismantle Obama’s climate legacy with executive order

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Tropical cyclone Debbie has made landfall in Queensland as a category 4 cyclone with winds of more than 150 kilometres per hour.

The cyclone crossed the coast near Airlie Beach on Tuesday afternoon. Reports of wind gusts in excess of 200km per hour and rainfall of more than 200mm of rain have been made in some areas along the central Queensland coast.

The Bureau of Meteorology forecasted an average to above-average number of Australian cyclones in its October severe weather outlook. Australia receives 11 cyclones on average each year, with about four of those in Queensland. Debbie is the fifth cyclone of the season for Australia as a whole and the most intense of the season so far.

Anomalously high moisture, warm ocean temperatures, and low environmental pressures seem to have created the conditions that allowed TC Debbie to form and grow in intensity.

Perfect storm

Tropical cyclones are low pressure systems that form over warm tropical oceans. The warmth and moisture of the oceans are what gives a cyclone its energy. The low pressure, which meteorologists measure in “hectopascals”, draws in the surrounding warm, moist air, which then rises into deep thunderstorm clouds. As the air is pulled into the centre of low pressure, Earth’s rotation causes it to spin cyclonically and it continues to intensify.

TC Debbie formed at the eastern end of an active monsoon trough extending from the Indian Ocean across the top of Australia and into the Coral Sea. The monsoon trough is a region of low air pressure and thunderstorms that forms over northern Australia in the summer months, bringing with it the wet season. On March 22, a large region of active thunderstorms began to organise into a weather disturbance off the eastern tip of Papua New Guinea.

Over the following two days the thunderstorms organised about a circulation centre as sea level pressures began to drop and moist air converged into the area. By late on March 24 a tropical depression, a forerunner of a cyclone, had formed and begun to drift south, making a long S-shaped track.

Tropical Cyclone Debbie was named on March 25. It then came under the influence of the subtropical ridge, a zone of stable high pressure that gives much of Australia fine weather during the summer. This drove Debbie west-southwest towards the Queensland coast while it gradually intensified further.

Because of the relatively high amounts of moisture in the atmosphere, and relatively warm ocean waters, Debbie intensified to category 4 by 10 pm on March 27, with the strongest wind gusts reaching 225-280km per hour. On Tuesday afternoon Debbie was a strong category 4 cyclone with a central pressure of 943 hectopascals and surface sustained winds of 185 kilometres per hour. The Bureau of Meteorology downgraded TC Debbie to a category 3 at 4:00 pm EST.

To put Debbie in context, there has been only one cyclone since 1980 to have made landfall in Queensland with a lower central pressure. That was Yasi in 2011.

Of the 46 cyclones to have made landfall in Queensland since 1980, only three others arrived at the coast with pressures of less than 960 hectopascals: Dominic in 1982, Winifred in 1986, and Ingrid in 2005.

Predicting cyclones

Tropical cyclone forecasters use a variety of tools to forecast the storm’s track, intensity, storm surge, and rainfall. Because it is difficult to obtain observations of wind at ocean’s surface under a cyclone, meteorologists have developed tools based on satellite imagery to estimate a storm’s intensity, location, and where the strongest and most destructive winds are found.

Several models are also used to aid in making forecasts – from the complex numerical weather prediction models, to statistical models. Models start by using observations of the atmosphere, and then use these data to make a forecast.

Depending on their level of complexity the models can predict the future track, intensity, rainfall, wave height, and/or storm surge. The forecasters access all of this information to then make their forecast.

Cyclone forecasts have improved considerably over time. In particular, track forecasts have improved so that the 48-hour forecast is now more accurate than the 24-hour ones were back in the early 1990s. Track forecasting has become so reliable that the US National Hurricane Centre now produces 120-hour track forecasts.

Intensity forecasts have improved more slowly, but as models have become more refined and satellite technology has improved, the ability of forecasters to accurately estimate and predict intensity is also getting gradually better.

The prediction of rainfall, the extent of the damaging wind field, and storm surge forecasts are also slowly improving. Now that they are receiving more attention, we can expect considerable improvements in these over the next decade.

Liz Ritchie-Tyo receives funding from the U.S. National Science Foundation.

Hazelwood's closure does not mean imminent blackouts for Victoria. Takver/Flickr, CC BY-SA

Victoria’s Hazelwood power station will be shut down this week after nearly 50 years of supplying electricity.

The imminent closure has led to concerns about blackouts, raised most recently by Deputy Prime Minister Barnaby Joyce, and rising electricity prices.

So what does the evidence suggest?

Blackouts ahead?

Last week The Age reported that Victoria is facing “72 days of possible power supply shortfalls over the next two years”. While that sounds bad, it does not mean the state is facing imminent blackouts.

This was based on a report from the Australian Energy Market Operator (AEMO), which is in charge of making sure that Australia’s energy markets work.

Every week, AEMO produces something called the Medium Term Projected Assessment of System Adequacy. This report assesses the expected supply and demand of electricity for the next two years.

In a recent report, AEMO did indeed forecast a “reserve shortfall” for 72 days in Victoria in the coming two years. AEMO has actually been forecasting many days of reserve shortfall, since early November last year when Engie announced the closure of Hazelwood.

AEMO has also been forecasting an even greater number of days of reserve shortfalls in South Australia for well over a year.

The shortfall forecast is based on a combination of factors. This includes the amount of local energy supply, the import and export of electricity from other states, the maximum daily demand for electricity, and the “reserve requirement”. The reserve requirement is essentially “spare” capacity that can be used to maintain a reliable supply if something goes wrong.

If there is not enough supply to meet this requirement, there is a reserve shortfall.

Forecasting maximum demand is incredibly challenging and uncertain. AEMO does it by using probabilities. This gives us a measure of the probability of a particular demand forecast being exceeded in a year.

For example, a 10% chance would be expected to be exceeded one year in ten. A 50% chance would be expected to be exceeded one year in two.

To illustrate the point, AEMO forecast that demand over the past summer in Victoria had a 10% chance of exceeding 9,900 megawatts. In reality, the maximum demand was only 8,747MW. That’s not to say the forecast was wrong, but rather that it was not an exceptional (one year in ten) summer.

In the recent outlook, AEMO has found 72 days on which a reserve shortfall might occur. The likelihood of this happening on any one of those days is low. For a reserve shortfall to actually occur 72 times over two years is incredibly unlikely.

However, AEMO still plans for this possibility. Indeed, this is largely the point of producing these forecasts: signalling potential capacity shortfalls so the market and operator can respond.

What will happen when Hazelwood closes?

Another way of illustrating the role of Hazelwood and the effect of its closure on the broader Victorian energy system is shown below.

In this figure, I’ve plotted the 10% and 50% thresholds for exceeding maximum demand in the coming summer, and also the “load duration curve” for previous years. This curve shows that the periods of greatest demand are also the least common (the left side of the graph). The vast majority of demand is much lower, and the “base load” is about 4,000MW.

† Interconnection capacity (from other states) at times of peak demand is much less than the total theoretically possible. ‡ Firm wind is about 7.5% of total rated capacity in Victoria. Author

I’ve also included “firm capacity” (the minimum power we know we can get) with and without Hazelwood, to the right.

As can be seen, there is more than enough capacity in Victoria to meet the base load. There is even enough local firm capacity to meet the peak load and reserve requirements for the one-in-two-year maximum demand event. For the one-in-ten-year event, power needs to be imported from other states to ensure secure supply at the peaks.

AEMO reaffirmed security of supply in a media statement last week. As noted, Victoria and other states have available power generation resources that are not switched on or are operating at less than full capacity. This electricity can be made available to replace the power that Hazelwood supplies.

What about prices?

The question of what replaces Hazelwood brings us to prices. Many, including AEMO, expect to see increased generation from currently underused power plants. These include New South Wales’ black coal power plants. Last year NSW’s black coal was used at 56% of its total capacity. Bumping up these stations’ output would also reduce NSW’s reliance on Victorian exports.

Reducing the capacity of brown coal will mean logically that Victoria relies on more expensive forms of generation such as black coal or gas. This is particularly so if the availability of cheap imports is limited, and more expensive local generation such as gas is needed.

Black coal power stations generate electricity comparatively cheaply. Even so electricity prices are already so high that an increase in black coal generation may not have a dramatic impact on prices. With NSW prices averaging A$137 per megawatt hour this year, it is clear that the cost of coal is not determining electricity prices.

The Victorian wholesale market will also become a more concentrated market. As a result, there may be more opportunities for market power to be exercised. Perhaps the recently announced ACCC inquiry into power prices will put generators on their best behaviour.

Any price rise may be short-lived. The Australian Energy Market Commission, which sets the rules for the energy market, has reported that more renewable energy supply is expected to reduce wholesale electricity prices.

Hazelwood’s closure should not compromise the security of the Victorian electricity system over the next few years. This is not to say that there definitely won’t be a blackout. A one-in-50-year storm, a plant failure, a flooded mine pit, an interconnector outage – any of these events could strain the system beyond what is manageable.

At this stage, what ultimately happens to prices is anyone’s guess. Whatever the case, it is clear that Victoria has plenty of supply to meet the state’s base load. New capacity might be required to meet the maximum demand – and that new capacity could take the form of energy storage.

Dylan McConnell has received funding from the AEMC's Consumer Advocacy Panel and Energy Consumers Australia.

After a startling encounter with a cuttlefish, Australian philosopher Peter Godfrey-Smith set out to explore the mysterious lives of cephalopods. He was left asking: why do such smart, optimistic creatures live such a short time?

Inches above the seafloor of Sydney’s Cabbage Tree Bay, with the proximity made possible by several millimetres of neoprene and an oxygen tank, I’m just about eyeball to eyeball with this creature: an Australian giant cuttlefish.

Even allowing for the magnifying effects of the mask snug across my nose, it must be about two feet long, and the peculiarities that abound in the cephalopod family, that includes octopuses and squid, are the more striking writ so large.

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Trump’s anti-science budget, anti-climate executive orders, and general disdain for scientific expertise come at a bad time

Today, Trump signed executive orders taking aim at America’s climate policies. On the heels of a report finding that the world needs to halve its carbon pollution every decade to avoid dangerous climate change, Trump’s order would instead increase America’s carbon pollution, to the exclusive benefit of the fossil fuel industry.

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Camera traps caught images of the critically endangered Indochinese tigers in eastern Thailand.

Amount of electricity demanded by homes and businesses one afternoon was lower than it was during night for first time ever

Last weekend’s sunny weather was not only good for beers, barbecues and bees, but also drove solar power to break a new UK record.

For the first time ever, the amount of electricity demanded by homes and businesses in the afternoon on Saturday was lower than it was in the night, because solar panels on rooftops and in fields cut demand so much.

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Takahama reactors, which Greenpeace says have serious unresolved safety issues, will restart within a month

Japan’s struggling nuclear power industry has won a victory against a landmark legal injunction that halted the running of two reactors.

Six years on from the triple-meltdown at Fukushima, the industry faces concerted opposition from residents and some officials due to lingering concerns about safety.

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Scientists have made a mini working replica of the female reproductive tract to experiment on.

Europe is going to investigate a second site on Mars - called Mawrth Vallis - as a possible destination to send its 2021 rover.

Trump’s climate blitzkrieg is unlikely to herald the end of civilization, but it risks US geopolitical dominance and could help ‘make China great again’

Is Donald Trump’s determination to send US climate change policy back into the dark ages an “existential threat to the entire planet”, as the architect of many of Barack Obama’s green measures warns? Or is global momentum towards a cleaner, safer future “unstoppable”, as the UN’s climate chief said recently?

Related: Trump begins tearing up Obama's years of progress on tackling climate change

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UK ranks fifth in table assessing EU actions to cut carbon emissions by 40%, with most countries gaining wiggle room via loopholes

Sweden, Germany and France are the only European countries pursuing environmental policies in line with promises made at the Paris climate conference, according to a new ranking study.

The UK is in fifth position in the table which assesses policy actions taken by EU states to meet Europe’s pledge of a 40% cut in carbon emissions by 2030.

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A senior researcher claims ministers are using a flawed method for assessing badger numbers in the TB cull.

SA Power Networks boss says price of rooftop solar and battery storage will fall to just 15c/kWh within a few years, which is less than half the cost of grid power.

The B6305 Allendale road, Northumberland Colours and sights shift across the seasons, all seen from this one road

It’s late morning and I’m driving from Allendale to Hexham along the straight road known as the Paise dyke. Cars bowl along here at speed, but to do that is to miss the far views and the birds. There’s always something to catch the eye. Ahead, on this warm March morning, starlings swarm like bees across the fields, a rushing wind as I drive under them, about 3,000 birds. The flock is so regularly spaced that I feel a vast net has been cast over me before they settle on a field pocked by mole hills and rich in worms.

There’s a farm and a wood called the Paise but the road’s name is not on the Ordnance Survey map. In his book published in 1970, Goodwife Hot and Others: Northumberland’s Past as Shown in Its Place Names, the historian and farmer Geoffrey Watson thought the name referred to land where peas were grown. Though these are upland fields, he believed they would have been adequate for growing this staple diet. The dyke might refer to a stone wall or a causeway over the boggy moorland.

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‘Environmental vandalism’ proposal would put vulnerable species, including Leadbeater’s possum and Sooty owl, at risk of extinction

A proposal to release areas of protected Victorian old-growth forest for logging is “environmental vandalism crossed with bad economics” that would put a number of vulnerable species at risk of extinction, a leading Leadbeater’s possum expert has said.

Professor David Lindenmayer, from the Australian National University, is recognised as the world expert in the critically endangered Leadbeater’s possum.

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AEMO’s final report into SA blackout sparks a social media spat between the state’s energy minister and The Australian’s Michael Owen.

Credit finance group FlexiGroup issues second CEFC-backed green bond to Australian market, tapping investor demand for residential rooftop solar and battery storage.

North East Water launches tender for solar and battery storage system to power Yackandandah water treatment plant – testing the water for the entire national sector.

Eyewitness accounts of large, dog-like animals in state’s far north spur scientific hunt for thylacines, thought to have died out in 1936

“Plausible” possible sightings of a Tasmanian tiger in north Queensland have prompted scientists to undertake a search for the species thought to have died out more than 80 years ago.

The last thylacine is thought to have died in Hobart zoo in 1936, and it is widely believed to have become extinct on mainland Australia at least 2,000 years ago.

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