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Former US Secretary of Defence, William J. Perry, warns that the risk of nuclear catastrophe is greater than it was during the Cold War and is growing every year. 

Multibillion-pound Hornsea Project Two, 55 miles off Grimsby coast, would see 300 turbines span an area five times size of Hull

The second phase of the world’s biggest offshore windfarm is set to be built off the Yorkshire coast after being approved by ministers.

The multibillion-pound Hornsea Project Two would see 300 turbines – each taller than the Gherkin – span an area five times the size of Hull.

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China successfully launches its first quantum-enabled satellite, named after the ancient Chinese scientist and philosopher Micius.

National Oceanic and Atmospheric Administration to classify disaster as the eighth flood considered to be a once in every 500-year event in the US in a year

The historic and devastating floods in Louisiana are the latest in a series of heavy deluges that some climate scientists warn will become even more common as the world continues to warm.

On Tuesday, the National Oceanic and Atmospheric Administration (Noaa) is set to classify the Louisiana disaster as the eighth flood considered to be a once in every 500-year event to have taken place in the US in little over 12 months.

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Artists teamed with photographer and volunteers to produce posters that will warn young people of air quality on some of the capital’s most polluted streets

Young Londoners concerned about air pollution from traffic have launched an independent billboard campaign to warn their peers of the dangers of diesel fumes.

Artists Vasilisa Forbes and Claire Matthews, together with photographer Terry Paul and a group of 16 to 25-year-old volunteers, have printed 12 large 20 x 12-foot posters which will appear for months on some of London’s most polluted streets.

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Results from a lab experiment have lent support to one of Stephen Hawking's most important predictions about black holes.

Leaders of the Munduruku people will be shown the storeroom’s head-dresses and other objects made by their tribe more than 150 years ago

Amazonian leaders, in Britain to protest against the construction of several large dams which they say will destroy the lives of thousands of indigenous people, will on Tuesday be shown head-dresses and other objects made by their tribe more than 150 years ago.

The two chiefs of the Munduruku civilisation, which has flourished peacefully for centuries by fishing and farming along the banks of the great Tapajós river and its tributaries in the rainforests of central Brazil, will visit the massive storeroom of the British Museum in London, where a collection of 50 objects brought to Britain by a Victorian merchant are kept.

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Professor Brian Cox has verbally sparred with a newly elected Australian politician Malcolm Roberts who believes climate change is a global conspiracy.

Scientists carrying out international nuclear fusion work are concerned dust from a planned quarry could affect their experiments.

The Tory government in the UK has finally woken up to the fact that solar and wind is cheaper than nuclear. It may mean a big shift in its energy strategy, as it focuses on distributed generation rather than mega projects. Shouldn't Australia be leading on this?

Leaked documents and sources show Natural England will use its legal powers less and seek funding from the private companies it is meant to keep in check

England’s nature watchdog is planning to use its legal powers less and risks becoming a weak regulator forced to raise funding from the private companies it is meant to keep in check, leaked documents and sources reveal.

Natural England is duty-bound to defend rare species and protected areas including national parks and England’s 4,000 sites of special scientific interest from potentially environmentally damaging developments.

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Energy Made Clean, WattWatchers and water cremation company named among 38 semi-finalists short-listed in 2016 Australian Technologies Competition.

Windbacks to solar subsidies may encourage larger systems. Solar panel image from www.shutterstock.com

Solar households in Victoria, South Australia and New South Wales will this year cease to be paid for power they export into the electricity grid. In South Australia, some households will lose 16 cents per kilowatt-hour (c/kWh) from September 31. Some Victorian households will lose 25 c/kWh, and all NSW households will stop receiving payments from December 31.

These “feed-in tariffs” were employed to kick-start the Australian solar photovoltaic (PV) industry. They offered high payments for electricity fed back into the grid from roof-mounted PV systems. These varied from state to state and time to time.

For many householders, these special tariffs are ending. Their feed-in tariffs will fall precipitously to 4-8 c/kWh, which is the typical rate available to new PV systems. In some cases households may lose over A$1,000 in income over a year.

But while the windback may hurt some households, it may ultimately be a good sign for the industry.

What can households do?

At present, householders with high feed-in tariffs are encouraged to export as much electricity to the grid as possible. These people will soon have an incentive to use this electricity and thereby displace expensive grid electricity. This will minimise loss of income.

Reverse-cycle air conditioning (for space heating and cooling) uses a lot of power that can be programmed to operate during daylight hours when solar panels are most likely to be generating electricity. The same applies to heating water, either by direct heating or through use of a heat pump. For heating water, solar PV is now competitive with gas, solar thermal and electricity from the grid.

Batteries, both stationary (for house services) and mobile (for electric cars), will also help control electricity use in the future.

A boost for the industry?

The ending of generous feed-in tariffs is likely to modestly encourage the solar PV industry. This is because many existing systems have a rating of only 1.5 kilowatts (kW), which could not have been increased without loss of the generous feed-in tariff.

Many householders will now choose to increase the size of their PV system to 5-10kW – in effect a new system given the disparity in average PV sizing between then and now.

A new large-scale PV market is also opening on commercial rooftops. Many businesses have daytime electrical needs that are better matched to solar availability than are domestic dwellings.

This allows businesses to consume the large amounts of the power their panels produce and hence minimise high commercial electricity tariffs. The constraining factors in this market are often not technical or economic, and include the fact that many businesses rent from landlords and tend to have short terms for investment. Business models are being developed to circumvent these constraints.

The rooftop PV market also now has large potential in competing with retail electricity prices. The total cost of a domestic 10kW PV system is about A$15,000. Over a 25-year lifetime this would yield an energy cost of 7 c/kWh.

This is about one-quarter of the typical Australian retail electricity tariff, about half of the off-peak electricity tariff, and similar to the typical retail gas tariff. Rooftop PV delivers energy services to the home more cheaply than anything else and has the capacity to drive natural gas out of domestic and commercial markets.

According to the Australian Bureau of Statistics, there are 9 million dwellings in Australia, and the floor area of new residential dwellings averaged 200 square metres over the past 20 years. Some of these dwellings are in multi-storey blocks, others have shaded roofs and, of course, south-facing roofs are less suitable than other orientations for PV.

However, if half the dwellings had one-third of their roofs covered in 20% efficient PV panels then 60 gigawatts (GW) could be accommodated. For perspective, this would cover 40% of Australian electricity demand. Commercial rooftops are a large additional market.

Solar getting big

Virtually all PV systems in Australia are roof-mounted. However, this is about to change because ground-mounted PV systems are becoming competitive with wind energy. We can see the falling cost of solar in the Queensland Solar 120 scheme, the Australian Capital Territory wind and PV reverse auctions and the Australian Renewable Energy Agency Large Scale Solar program , which all point to the declining cost of PV and wind.

Together, wind and PV constitute virtually all new generation capacity in Australia and half of the new generation capacity installed worldwide each year.

The total cost of a 10-50 megawatt PV system (1,000 times bigger than a 10kW system) is in the range A$2,100/kW (AC). A 25-year lifetime yields an energy cost of 8 c/kWh. This is only a little above the cost of wind energy and is fully competitive with new coal or gas generators.

Hundreds of 10-50MW PV systems can be distributed throughout sunny inland Australia close to towns and high-capacity powerlines. Australia’s 2020 renewable energy target is likely to be met with a large PV component, in addition to wind.

Wide distribution of PV and wind from north Queensland to Tasmania minimises the effect of local weather and takes full advantage of the complementary nature of the two leading renewable energy technologies.

The declining cost of PV and wind, coupled with the ready availability of pumped hydro storage, allows a high renewable electricity fraction (70-100%) to be achieved at modest cost by 2030.

Andrew Blakers receives research funding from the Australian Renewable Energy Agency, the Australian Indonesian Centre, the Australian Research Council, Excellerate Australia and private companies.

In an entertaining and somewhat chaotic episode of ABC’s Q&A (Monday 15th August) pitching science superstar Brian Cox against climate contrarian and global conspiracy theorist and now senator Malcolm Roberts, the question of cause and effect and empirical data was raised repeatedly in regard to climate change.

Watching I pondered on a question - what would it take me to change my mind? After all, I should dearly love to be convinced that climate was not changing, or if it were, it were not due to our unrelenting emissions of CO2 and other greenhouse gases. That would make things just so much easier, all round.

So what would make me change my mind?

There are two elements to this question. The first is the observational basis, and the question of empirical data. The second relates to cause and effect, and the question of the greenhouse effect.

On the second, I will only add that the history of our planet is not easily reconciled without recourse to a strong greenhouse effect. If you have any doubt then you simply need to read my former colleague Ian Plimer.
As I have pointed out before, in his 2001 award-winning book “A Short History of Planet Earth”, Ian has numerous references to the greenhouse effect especially in relation to what all young geologists learn as the faint young sun paradox:

“The early sun had a luminosity of some 30 per cent less than now and, over time, luminosity has increased in a steady state.”

“The low luminosity of the early sun was such that the Earth’s average surface temperature would have been below 0C from 4500 to 2000 million years ago. But there is evidence of running water and oceans as far back as 3800 million years ago.”

The question is, what kept the early Earth from freezing over?

Plimer goes on to explain: “This paradox is solved if the Earth had an enhanced greenhouse with an atmosphere of a lot of carbon dioxide and methane.”

With Ian often touted as one of the grand priests of climate contrarians, I doubt that Malcolm would consider him part of the cabal of global climate change conspiracists, though that would be ironic.

As a geologist, I need to be able to reconcile the geological record of a watery planet from time immemorial with the faint young sun hypothesis. And, as Ian points out, with nothing else on the menu, the greenhouse effect is all we have.

If the menu changes, then I will reconsider.

How about the empirical data?

Along with Brian Cox, I find it implausible that an organisation like NASA, with a record of putting a man on the moon, could or would fabricate data to the extent Malcolm Roberts insinuates. It sounds such palpable nonense, it is something you might expect from an anti-vaxer.

However, a clear message from the Q&A episode is there is no way to convince Malcolm Roberts that the meteorological temperature data has not been manipulated to achieve a predetermined outcome. So he simply is not going to accept those data as being empirical.

However, the relevant data does not just include the records taken by meteorological authorities. It also includes the the record preserved beneath our feet in the temperature logs from many thousands of boreholes across all inhabited continents. And the importance of those logs is that they are reproducible. In fact Malcolm can go out an re-measure them himself, if he needs convincing they are “emprical”.

The idea that the subsurface is an effective palaeo-thermometer is a simple one that we use in our every day life, or used to at least prior to refrigeration, as it provides the logic for the cellar.

When we perturb the temperature at the surface of the earth, for example as the air temperature rises during the day, it sends a heat pulse downwards into the earth. The distance the pulse travels is related to its duration. As the day turns to night and the surface cools, a cooling pulse will follow, lagging behind, but eventually cancelling, the daily heating. The diurnal surface temperature perturbations produce a wave like train of heating and cooling that can felt with diminishing amplitude down to a skin depth less than a metre beneath the surface before all information is cancelled out, and the extremes of both day and night are lost.

Surface temperatures also change on a seasonal basis from summer to winter and back again, and those temperatures propagate even further to depths of around 10 metres before completely cancelling [1].

On even longer cycles the temperature anomalies propagate much further, and may reach down to a kilometre or more. For example, we know that over the last million years the temperature on the earth has cycled in an out of numerous ice ages, on a cycle of about 100,000 years. Cycles on that timescale can propagate more than one kilometre into the earth, as we see in deep boreholes, such as the Blanche borehole near the giant Olympic Dam mine in South Australia. From our analysis of the Blanche temperature logs we infer a surface temperature amplitude of around 8°C over the glacial cycle.

So what do we see in the depth range of 20-100 metres that is sensitive to the last 100 years, and most relevant to the question of changing climate?

The image below shows the temperature log from a borehole that we purpose drilled in Gippsland as part of AuScope AGOS program.

Temperature log in the upper 70 metres of the Tynong AGOS borehole drilled and cored to a depth of 500 metres. The temperature logs shown here were obtained by Kate Gordon, as a student at the University of Melbourne.

The temperature profile shows various stages. Above the water table at about 15 metres depth, due to infiltration of groundwater in the vadose zone, the temperatures in the borehole rapidly equilibrate to seasonal surface temperature changes. In the winter, when this temperature log was obtained, the temperatures in this shallow zone trend towards the ambient temperature around 12°C. In summer, they rise to over 20°C. Beneath the vadose zone, the temperature in the borehole responds to the conduction of heat influenced by two dominant factors, the changing surface temperature on time-scales of decades to many hundred of years, and the heat flow from the deeper hot interior of the earth. During a rapid surface warming cycle lasting more than several decades the normal temperature gradient in which temperatures increase with depth can be reversed, so that we get a characteristic rollover (with a minimum here seen at about 30 depth).

Inversion of the Tynong temperature log for surface temperature change over the last 700 years, with uncertainties at the 95% confidence interval. The inversion, which is based on Fourier’s law of heat conduction, shows that we can be confident that the Tynong AGOS borehole temperature record is responding to a long-term heating cycle of 0.3-1.3°C over the last century at the 95% confidence level. The inversion shown here was performed by Kate Gordon.

In geophysics we use the techniques of inversion to identify causative signals, and their uncertainties, in records such as the Tynong borehole log, as well as in the estimation of the value of buried ore bodies and hydrocarbon resources. As shown in the second image, the inversion of the Tynong temperature log for surface temperature change over the last 700 years, with uncertainties at the 95% confidence interval, is compelling. Not surprisingly as we go back in time the uncertainties become larger. However, the inversion, which is based on Fourier’s law of heat conduction, shows that we can be confident that the Tynong AGOS borehole temperature record is responding to a long-term heating cycle of 0.3-1.3°C over the last century at the 95% confidence level.

If there were just one borehole that showed this record, it would not mean much. However the characteristic shallow rollover is present in all the boreholes we have explored, and has been reported in many thousands of boreholes from all around the world.

The only way we know to sensibly interpret such empirical evidence is that ground beneath our feet, down to a depth of around 50 metres or so is now heating from above. The physics that explains these observations dates back to Joseph Fourier, over 200 years ago, so its not exactly new or even contentious. In effect the solid earth below is now absorbing heat from the atmosphere above, counter to the normal process of loosing heat to it. However, if Malcolm can bring to the table an alternative physics to explain these observations, while not falling foul of all the other empirical observations that Fourier’s law of heat conduction admits, then I am happy to consider, and put it to the test. (I suspect Brian Cox would be too, since all good physicists would relish the discovery of a new law of such importance as Fourier’s law).

Perhaps the hyper-skeptical Malcolm thinks that somehow the global cabal of climate scientists has got into all these thousands of boreholes with an electrical heater to propagate the heat signal that artificially simulates surface heating. More fool me.

But, if he does, then I am perfectly happy to arrange to drill a new borehole and, along with him, measure the temperature profile, making sure we don’t let those pesky climate scientists get at the hole with their heating coils before we have done so.

And I’ll bet him we can reproduce the signal from Tynong shown above.

But I’ll only do it on the condition that Malcolm agrees, that when we do (reproduce the signal), he will publicly acknowledge the empirical evidence of a warming world entirely consist with NASA’s surface temperature record.

Malcolm, are you on? Will you take on my bet, and use the Earth’s crust as the arbiter? and perhaps Brian will stream live to the BBC?

Disclosure

Mike Sandiford receives funding from the Australian Research Council to investigate the thermal structure of the Australian crust.

Claxton, Norfolk Surely more than anything else in British nature, swifts symbolise all of life, and it is all here now in the line of that curve

My summer’s highlight, as we sit in the garden most evenings, has been to watch the pre-migration flocking behaviour of our village swifts. No one knows what purpose it serves, though it’s thought to play some role in flock cohesion. Up to 30 birds were involved, all crushed into a ravelling ball of anarchy burning across the heavens. I find it all the more magnificent to know that its whole ecology is based entirely on insects, but converted to swift speed and scream.

Like the flock itself I circle around and around, but no fishing net of words seems to catch it. Could one possibly express it better as a taste? It is like red chilli crushed in a gloop of honey; the essence of all the Americas mingled with that from all Africa and Eurasia; a taste, perhaps, of Pangaea.

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The reign of record hot months in 2016 continues, with last month claiming the title of hottest July on record globally, according to data released by NASA on Monday.

British particle physicist Brian Cox verbally spars with a newly elected Australian politician who believes climate change is a global conspiracy.

We probably have only about a decade before we break through the ambitious 1.5℃ global warming target agreed to by the world’s nations in Paris.

Madagascar's conservationists work in secrecy to protect one of the world's most beautiful tortoises from poachers, writes journalist Martin Vogl.

Nasa’s results, which combine sea-surface temperature and air temperature on land, show July was 10th month in a row to break monthly temperature record

Last month was the hottest month in recorded history, beating the record set just 12 months before and continuing the long string of monthly records, according to the latest Nasa data.

The past nine months have set temperature records for their respective months and the trend continued this month to make 10 in a row, according to Nasa. July broke the absolute record for hottest month since records began in 1880.

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