Climate Change: How Do We Know?

NASA

This graph, based on the comparison of atmospheric samples contained in ice cores and more recent direct measurements, provides evidence that atmospheric CO₂ has increased since the Industrial Revolution. (Credit: Vostok ice core data/J.R. Petit et al.; NOAA Mauna Loa CO2 record.) Find out more about ice cores (external site).

The Earth's climate has changed throughout history. Just in the last 650,000 years there have been seven cycles of glacial advance and retreat, with the abrupt end of the last ice age about 7,000 years ago marking the beginning of the modern climate era — and of human civilization. Most of these climate changes are attributed to very small variations in Earth's orbit that change the amount of solar energy our planet receives.

Scientific evidence for warming of the climate system is unequivocal.
- Intergovernmental Panel on Climate Change

The current warming trend is of particular significance because most of it is extremely likely (greater than 95 percent probability) to be the result of human activity since the mid-20^th century and proceeding at a rate that is unprecedented over decades to millennia.¹
Earth-orbiting satellites and other technological advances have enabled scientists to see the big picture, collecting many different types of information about our planet and its climate on a global scale. This body of data, collected over many years, reveals the signals of a changing climate.
The heat-trapping nature of carbon dioxide and other gases was demonstrated in the mid-19th century.² Their ability to affect the transfer of infrared energy through the atmosphere is the scientific basis of many instruments flown by NASA. There is no question that increased levels of greenhouse gases must cause the Earth to warm in response.
Ice cores drawn from Greenland, Antarctica, and tropical mountain glaciers show that the Earth's climate responds to changes in greenhouse gas levels. Ancient evidence can also be found in tree rings, ocean sediments, coral reefs, and layers of sedimentary rocks. This ancient, or paleoclimate, evidence reveals that current warming is occurring roughly ten times faster than the average rate of ice-age-recovery warming.³

The evidence for rapid climate change is compelling:

Sea level rise Image: Republic of Maldives: Vulnerable to sea level rise Global sea level rose about 8 inches in the last century. The rate in the last two decades, however, is nearly double that of the last century.4 Links Earth's vital signs: Sea Level Quiz: Sea level	Global temperature rise The planet's average surface temperature has risen about 2.0 degrees Fahrenheit (1.1 degrees Celsius) since the late 19th century, a change driven largely by increased carbon dioxide and other human-made emissions into the atmosphere.5 Most of the warming occurred in the past 35 years, with 16 of the 17 warmest years on record occurring since 2001. Not only was 2016 the warmest year on record, but eight of the 12 months that make up the year — from January through September, with the exception of June — were the warmest on record for those respective months.6 Links Earth's vital signs: Global temperature Global Climate Change: Causes Graphic: Global warming from 1880 to 2015
Warming oceans The oceans have absorbed much of this increased heat, with the top 700 meters (about 2,300 feet) of ocean showing warming of 0.302 degrees Fahrenheit since 1969.7 Links Climate Kids: What is happening in the ocean? Video: Oceans of climate change Article: Warming ocean causing most Antarctic ice shelf mass loss	Shrinking ice sheets Image: Flowing meltwater from the Greenland ice sheet The Greenland and Antarctic ice sheets have decreased in mass. Data from NASA's Gravity Recovery and Climate Experiment show Greenland lost 150 to 250 cubic kilometers (36 to 60 cubic miles) of ice per year between 2002 and 2006, while Antarctica lost about 152 cubic kilometers (36 cubic miles) of ice between 2002 and 2005. Links Vital Signs: Land Ice Global Ice Viewer
Declining Arctic sea ice Image: Visualization of the 2007 Arctic sea ice minimum Both the extent and thickness of Arctic sea ice has declined rapidly over the last several decades.8 Links Earth's vital signs: Sea ice Interactive: Global ice viewer NASA's Operation Icebridge mission	Glacial retreat Image: The disappearing snowcap of Mount Kilimanjaro, from space. Glaciers are retreating almost everywhere around the world — including in the Alps, Himalayas, Andes, Rockies, Alaska and Africa.9 Link Interactive: Global ice viewer
Extreme events The number of record high temperature events in the United States has been increasing, while the number of record low temperature events has been decreasing, since 1950. The U.S. has also witnessed increasing numbers of intense rainfall events.10 Links Precipitation Measurement Missions Precipitation Quiz	Ocean acidification Since the beginning of the Industrial Revolution, the acidity of surface ocean waters has increased by about 30 percent.11, 12 This increase is the result of humans emitting more carbon dioxide into the atmosphere and hence more being absorbed into the oceans. The amount of carbon dioxide absorbed by the upper layer of the oceans is increasing by about 2 billion tons per year.13, 14 Links How does climate change affect coral reefs The Other Carbon Dioxide Problem
Decreased snow cover Satellite observations reveal that the amount of spring snow cover in the Northern Hemisphere has decreased over the past five decades and that the snow is melting earlier.15 Links National Snow and Ice Data Center Earth Observatory: Snow Cover

References

1. IPCC Fifth Assessment Report, Summary for Policymakers
   B.D. Santer et.al., "A search for human influences on the thermal structure of the atmosphere," Nature vol 382, 4 July 1996, 39-46
   Gabriele C. Hegerl, "Detecting Greenhouse-Gas-Induced Climate Change with an Optimal Fingerprint Method," Journal of Climate, v. 9, October 1996, 2281-2306
   V. Ramaswamy et.al., "Anthropogenic and Natural Influences in the Evolution of Lower Stratospheric Cooling," Science 311 (24 February 2006), 1138-1141
   B.D. Santer et.al., "Contributions of Anthropogenic and Natural Forcing to Recent Tropopause Height Changes," Science vol. 301 (25 July 2003), 479-483.
2. In the 1860s, physicist John Tyndall recognized the Earth's natural greenhouse effect and suggested that slight changes in the atmospheric composition could bring about climatic variations. In 1896, a seminal paper by Swedish scientist Svante Arrhenius first predicted that changes in the levels of carbon dioxide in the atmosphere could substantially alter the surface temperature through the greenhouse effect.
3. National Research Council (NRC), 2006. Surface Temperature Reconstructions For the Last 2,000 Years. National Academy Press, Washington, D.C.
   http://earthobservatory.nasa.gov/Features/GlobalWarming/page3.php
4. https://www.ipcc.ch/pdf/assessment-report/ar5/syr/AR5_SYR_FINAL_SPM.pdf
   Church, J. A. and N.J. White (2006), A 20th century acceleration in global sea level rise, Geophysical Research Letters, 33, L01602, doi:10.1029/2005GL024826.
   The global sea level estimate described in this work can be downloaded from the CSIRO website.
5. https://www.ncdc.noaa.gov/indicators/
   http://www.cru.uea.ac.uk/cru/data/temperature
   http://data.giss.nasa.gov/gistemp
6. https://www.giss.nasa.gov/research/news/20170118/)  
7. Levitus, et al, "Global ocean heat content 1955–2008 in light of recently revealed instrumentation problems," Geophys. Res. Lett. 36, L07608 (2009).
8. L. Polyak, et.al., "History of Sea Ice in the Arctic," in Past Climate Variability and Change in the Arctic and at High Latitudes, U.S. Geological Survey, Climate Change Science Program Synthesis and Assessment Product 1.2, January 2009, chapter 7
   R. Kwok and D. A. Rothrock, "Decline in Arctic sea ice thickness from submarine and ICESAT records: 1958-2008," Geophysical Research Letters, v. 36, paper no. L15501, 2009
   http://nsidc.org/sotc/sea_ice.html
9. National Snow and Ice Data Center
   World Glacier Monitoring Service
10. "Attribution of Extreme Weather Events in the Context of Climate Change," National Academies Press, 2016
    https://www.nap.edu/read/21852/chapter/1
    Kunkel, K. et al, "Probable maximum precipitation and climate change," Geophysical Research Letters, (12 April 2013) DOI: 10.1002/grl.50334
    Kunkel, K. et al, "Monitoring and Understanding Trends in Extreme Storms: State of the Knowledge," Bulletin of the American Meteorological Society, 2012.
    http://lwf.ncdc.noaa.gov/extremes/cei.html
11. http://www.pmel.noaa.gov/co2/story/What+is+Ocean+Acidification%3F
12. http://www.pmel.noaa.gov/co2/story/Ocean+Acidification
13. C. L. Sabine et.al., "The Oceanic Sink for Anthropogenic CO2," Science vol. 305 (16 July 2004), 367-371
14. Copenhagen Diagnosis, p. 36.
15. National Snow and Ice Data Center
    C. Derksen and R. Brown, "Spring snow cover extent reductions in the 2008-2012 period exceeding climate model projections," GRL, 39:L19504
    http://nsidc.org/cryosphere/sotc/snow_extent.html
    Rutgers University Global Snow Lab, Data History Accessed August 29, 2011.

Adani Is Not Just Another Coalmine, It Is A Turning Point For The Nation

The Guardian - Hamish McKenzie

If the government approves this monstrous mine it will be committing environmental treason against every Australian who values our farmers, our coasts, our bush and our way of life

Protesters in Canberra hold banners and signs during a 12 April demonstration against Indian company Adani Enterprises building one of the world’s biggest coal mines in Australia. Photograph: Reuters

In an almost unbroken line from Monkey Mia, down across the Bight and then all the way up the other side to Mackay, the Australian coast is etched in various shades of brown. This is the historical precipitation map. Annual rainfall has dropped, it shows, across this enormous stretch of coastline, by as much as 100 millilitres since 1951.
In another map, concentric rings of increasingly angry red emanate from the centre of the continent. This one shows that, assuming we keep going as we are, the temperature in our country will increase by as much as 5C by the end of the century. Eight, if we’re unlucky.
This, by the way, is not the marketing material of some lefty environmental organisation. This is the product of thousands of the world’s top climate scientists, using some of the most sophisticated computer models ever built, to generate projections so fine-grained they simulate even the amount of moisture in every parcel of soil on the planet, and in the poles, the thickness of every chunk of sea ice.
These models give a glimpse of the Australia we are creating. They show the nation’s wheatbelts, from Esperance to the Wimmera, dried to a crisp. They show the Queensland coast being thrashed more relentlessly by fiercer storms. They show a rash of summer bushfires that make Black Saturday look like candles on a cake. But they do not show the reef. By the end of the century, we will have boiled it to death.
This is the Australia we are creating. Even more, it is the Australia we will have to accept if the Adani mine is approved.
Research published last year by four Oxford economists and scientists concluded that to keep climate change to below 2C, no new coal plants can be built after 2017 unless they have zero emissions. That means perfectly efficient carbon capture and storage would have to be deployed on every coal plant in the world – an absurd fantasy.

The paper also finds we already have in place sufficient “capital stock” – the global network of mines and electricity generators – to push us over 2C. At the same time, global coal demand has already peaked and is now falling, China and India have frozen construction on over 100 coal plants, and the economics of energy are pointing only in one direction: renewables.
This points to a stark lose-lose equation for potential new mines like Adani’s: either we burn their coal and induce dangerous climate change, or we don’t and waste billions of dollars.
Unless, of course, we take the third option: don’t build the thing. This is not, then, just another coalmine. It is a turning point. If we build Adani, we commit to irreparably harming Australia’s precious environment. If we don’t, we might still have a chance to save it. This is where we as a nation decide if we will be Asia’s rockpit for another 50 years, or a prosperous nation for the next 500.
Research just released shows that to avoid dangerous climate change, we need anthropogenic emissions to halve every decade. Building the biggest coalmine in history, when there is already a global glut and sufficient investment to tip us over the edge, is not what responsible conservative governments should be doing. They should be conserving all that is precious to us. Serving us. Instead, they are preparing to betray us.
If the world in 2077 is still burning as much coal as we are today, and the financial model of the Adani assumes it will, Australia as we know it – our wheatbelts, our reefs, our cities, and our lifestyles – will cease to exist.
Our government, sworn to protect the nation, should be doing everything it can to avert this looming crisis, not be falling over themselves to pay for the executioner’s bullet. If the government approves this monstrous mine, and the banks fund it, it will be committing environmental treason against every Australian who values our farmers, our coasts, our bush, and our way of life. We are about to choose Adani or Australia.
The argument against Adani achieves that rare distinction of finding purchase among all parts of society: patriots and cosmopolitans, environmentalists and economists, parochialists and internationalists, the job-hungry regions and the growth-hungry cities. We must all stop this affront to our nation. We must choose Australia.

Links

• The Adani mine is this generation's Franklin River. People power can stop it
• It’s either Adani or the Great Barrier Reef. Are we willing to fight for a wonder of the world?
• Footage shows wetlands blackened by Abbot Point coal dust, activists say
• Adani mine must stand on its own two feet, Labor's Jason Clare says
• Loss of coral reefs caused by rising sea temperatures could cost $1tn globally
• Malcolm Turnbull tells Indian billionaire native title will not stop Adani coalmine
• Coalition backbencher breaks ranks with colleagues over $1bn Adani rail loan
• Adani mine needs $1bn public funding to go ahead, Barnaby Joyce says
• It's either Adani or the Great Barrier Reef. Are we willing to fight for a wonder of the world?
• Don't fund coal mine, activists plead with Australian export credit agency
• Adani mine railway loan would breach government's policy, says legal group
• 'Irreversible consequences': Adani coalmine granted unlimited water access for 60 years
• The Adani mine is this generation's Franklin River. People power can stop it
• Labor to support native title changes to protect mining deals
• Ian and Greg Chappell call on Adani to abandon Carmichael mine project
• Stopping global warming is only way to save Great Barrier Reef, scientists warn

How High Will Global Sea Levels Rise?

Cosmos - James Mitchell Crow

Predicting the rate of Antarctica's ice melt is tricky business as the rise in global sea levels depends on the state of the ice cap. New research suggests it may be worse than we thought, writes James Mitchell Crow.

In the low-lying Netherlands, floating houses such as these in Ijberg, a suburb of Amsterdam, are ready for higher sea levels. Whether housing in other places should be built this way depends largely on what happens with Antarctica. Ashley Cooper / Getty Images

Estimates of global sea level rise by 2100 have fluctuated wildly in recent decades – from more than two metres to as little as 31 centimetres.
The rubbery figures have been a source of ammunition for climate change sceptics and consternation for policy makers – undermining their ability to plan ahead. Most of the blame can be levelled at Antarctica. Its 30 million km3 ice sheet holds 90 per cent of the world's fresh water. If it all melted, sea levels would rise 60 metres. By contrast, a melt of the Greenland ice sheet, the world's second largest, would contribute six metres.
Predicting the rate of ice melt in Greenland is relatively straightforward; Antarctica's melt is anything but.
The stability of Antarctica's ice sheet depends on the floating ice shelves at its fringes. They act as plugs halting the movement of the ice sheet. It is the dynamics of that interaction that have been hard to fathom.
The most recent IPCC report (published in 2013) estimated Antarctic ice would contribute just 4 centimetres to global sea levels by the end of the century, leading to an overall rise of 70 centimetres by the end of the century under "business as usual" emissions scenarios.
That estimate, according to Nick Golledge, an Antarctic ice sheet modeller at Victoria University of Wellington, in New Zealand, was extremely conservative, because the report's authors "just didn't know enough about fast dynamics in ice sheets". Scientific understanding has moved on since then, confirming Antarctica will contribute way more than 4 centimetres by 2100. "The latest research is converging on a figure more like half a metre," Golledge says.
Researchers discovered how unpredictable ice sheet dynamics could be in 2002 when a 3,500 km2 chunk of the Larsen B ice shelf disintegrated. Located on the Antarctic Peninsula, the continent's most northerly and warmest point, it had appeared perfectly stable.
While the melting of Larsen B didn't make any direct difference to sea levels (just as the melting of an ice block won't raise the level of your drink), it was the canary in the coal mine.
Before the Larsen B event, scientists thought the ice sheet moved in a very steady fashion, says Matt King, who researches Antarctica's contribution to sea level rise at the University of Tasmania. "You could kick it as much as you like and it didn't really do much... Now we have a completely different view."
What led to the collapse of Larson B was the rising summer temperatures in the Antarctic peninsula, with the mercury spending more and more time above zero in the years beforehand. As a result, vast pools of meltwater formed on top of the thinning ice, fracturing it and pouring into cracks that ultimately broke apart the whole chunk.
Summer surface melting is a well-understood process, and the dominant factor in Greenland's melt – making it highly predictable. The process can explain what is happening in the northern tip of Antarctica, but it can't account for the changes seen in the rest of the southern continent, where temperatures perpetually remain well below freezing. Here the peril seems to come from below.
One "hotspot" in East Antarctica is the rapidly thinning ice shelf fringing the large Totten glacier. In a study published in Science Advances in December 2016, a CSIRO-led team confirmed warm water from the deep ocean is slipping up onto the Antarctic continental shelf and reaching Totten via deep canyons in the sea floor.

As the ice warms, thins and cracks, yet another feedback mechanism might come into play, according to modelling.

"If there's one thing ice hates, it's warm water – it's tremendously efficient at melting ice," King says.
That warm water is not just a threat to the floating ice shelves. In West Antarctica the ice sheet sits on bedrock that is below sea-level, raising the risk warmer water could stream in and undercut the ice sheet.

Slip sliding away: Antarctica on the move. Cosmos DATA SOURCE: DeConto & Pollard, Nature, 2016.

As the ice warms, thins and cracks, yet another feedback mechanism might come into play, according to modelling by Robert DeConto at the University of Massachusetts and David Pollard at Pennsylvania State University. Each time a piece of ice shelf breaks off, the remaining "ice cliffs" will be taller. "That's inherently unstable," says Tony Worby, who heads the Antarctic Climate and Ecosystems Cooperative Research Centre in Hobart. Sooner or later the cliffs will crumble under their own weight.
Understanding these processes is just the beginning of the ice modellers' work. Predicting when, where and how rapidly they will occur, to forecast how much sea levels will rise, is quite another. So far the estimates of Antarctic contribution to sea level rise by 2100 remain highly variable. A key challenge is the lack of data to feed into the models. Huge sections of East Antarctica's coastal zone remain effectively unmapped. "We don't know where the bedrock is or where the warm water can flow," King says.
In 2019, Australian researchers will take delivery of a new icebreaker able to map the seafloor on Antarctica's fringe. The ship will carry an unmanned underwater vehicle capable of navigating under the ice shelves. "Very quickly we'll start to build a picture of what the seafloor looks like around the continental shelf around Antarctica," King says.
Within a decade, researchers should be more confident in their predictions. "Assuming," King notes, "there's not more unknown aspects of the ice sheet." We've been surprised before.

Links

• What happens if the permafrost disappears?
• How much ice can Antarctica afford to lose?
• Most sea-level rise since 1970 due to greenhouse gas emissions
• Short-term greenhouse gases cause long-term sea level rise
• Global warming levels masked by aerosols: study

Adani's Coal Will Worsen The Lives Of India's Poorest

Fairfax - Harita Sridhar*

Last week, I told my dad I was going to speak outside the Indian high commission at an anti-Adani rally against the proposed Carmichael mine. Soon after, he called me up and he was not happy.
My parents are Indian migrants and I am a young, second-generation, Indian-Australian woman. My father reminded me that there are 300 million people living without electricity in India, and of the times we ourselves were without power in our ancestral village and our home in the coastal city of Visakhapatnam.

Prime Minister Malcolm Turnbull met India's Adani Group founder and chairman Gautam Adani in Delhi on Monday. Photo: Mick Tsikas

He's right: energy poverty is an obstacle to inclusive development in India, and difficult to empathise with here in Australia, where we generally have the privilege of energy security.
But the coal from Adani's Carmichael mine is not the answer for those living without electricity. It will further pollute the air they breathe and the water they drink. It will cause dangerous climate change and extreme weather that always affects the poorest first. Australia's coal will make their lives harder in the long run.

A Stop Adani protest in Melbourne in December. Photo: Wayne Taylor

That's why I decided to speak out. I believe that, if the Australian government or Adani were genuinely serious about extending our energy security to India, they would be generous with technology transfer, or provide untied funding to help India's renewables sector grow. Instead, we face the potential construction of what would be Australia's largest coal mine, and the prospect of irreversible environmental degradation to our climate, groundwater and the Great Barrier Reef.
Adani's project is a terrible idea. The company has a record of serious environmental and human rights violations in several countries, including India I don't trust it to keep the Australian environment safe.
Prime Minister Malcolm Turnbull is offering Adani $1 billion of public money as a subsidised loan for this project, though India doesn't even want our coal! Just last week, India's Energy Minister, Piyush Goyal, said India didn't want to keep buying foreign coal and wanted instead to transition to a renewable-energy economy. This is the safer, cleaner and more sustainable solution to India's energy deficit, and the only one that doesn't harm the global environment.
Closer to home, more than two-thirds of Australians polled say they don't want the mine to be built either. This year alone, more than 140 "Stop Adani" groups have formed, and the national Stop Adani roadshow sold out at every major city along the east coast, gathering about 4000 passionate people (500 in Canberra!) who are concerned about the mine and don't want it to go ahead.
The Carmichael mine is bad for Australia, for India and for the global climate. The rest of the world is getting smarter about climate change and stepping away from coal. Australia shouldn't embarrass itself by taking a huge step backwards.

*Harita Sridhar is a Canberra student.

Links

• The Adani mine is this generation's Franklin River. People power can stop it
• It’s either Adani or the Great Barrier Reef. Are we willing to fight for a wonder of the world?
• Footage shows wetlands blackened by Abbot Point coal dust, activists say
• Adani mine must stand on its own two feet, Labor's Jason Clare says
• Loss of coral reefs caused by rising sea temperatures could cost $1tn globally
• Malcolm Turnbull tells Indian billionaire native title will not stop Adani coalmine
• Coalition backbencher breaks ranks with colleagues over $1bn Adani rail loan
• Adani mine needs $1bn public funding to go ahead, Barnaby Joyce says
• It's either Adani or the Great Barrier Reef. Are we willing to fight for a wonder of the world?
• Don't fund coal mine, activists plead with Australian export credit agency
• Adani mine railway loan would breach government's policy, says legal group
• 'Irreversible consequences': Adani coalmine granted unlimited water access for 60 years
• The Adani mine is this generation's Franklin River. People power can stop it
• Labor to support native title changes to protect mining deals
• Ian and Greg Chappell call on Adani to abandon Carmichael mine project
• Stopping global warming is only way to save Great Barrier Reef, scientists warn

Salt, Silicon Or Graphite: Energy Storage Goes Beyond Lithium Ion Batteries

The Guardian - Dyani Lewis

Technologies that use gels, liquids, and molten silicon or salt could all claim a slice of the growing renewable energy storage market

Solar power plants don’t produce energy when the sun doesn’t shine, but renewable energy storage batteries are becoming more competitive. Photograph: Tim Phillips Photos/Getty Images

Between the political bickering following a spate of blackouts in South Australia and the billionaire entrepreneur Elon Musk tweeting that he had a fix, and then the South Australian government announcing that it will build a grid-connected battery storage facility, interest in renewable energy storage has never been higher.
While lithium ion batteries sold by Tesla and others are perhaps the most widely known storage technology, several other energy storage options are either already on the market, or are fast making their way there.
All are hoping to claim a slice of what, by all indications, will be a very large pie. The Australian Energy Market Operator forecasts that more than 1.1m new battery storage systems will be installed in Australian households by 2035. And, according to a 2015 report by the Climate Council, battery storage capacity is expected to grow 50-fold in under a decade.
“The market for storage is huge,” says Kevin Moriarty, the executive chairman of 1414 Degrees, an Adelaide-based thermal storage company hoping to win South Australia’s 100MW storage system tender. The South Australian system will be the largest in Australia so far but Moriarty describes it as “a drop in the ocean” compared with what will be needed as Australia transitions away from carbon-dioxide emitting fossil fuels.
The need for energy storage solutions is the natural consequence of an energy grid that has an increasing amount of renewable energy sources. Solar power plants don’t produce energy when the sun doesn’t shine and windfarms grind to a halt when the wind doesn’t blow.
At the grid level, the resulting fluctuations in supply, combined with demand that can rapidly spike during hot weather, for example, can play havoc with the steady 50Hz electricity supply needed to power everything from microwaves to factory production lines.
Traditionally, fossil fuel-powered turbines are used to rapidly respond to load changes. If switched on when needed, electricity output ramps up or down so that there is enough electricity, at the right frequency, to supply demand.
Renewable energy storage systems, which include batteries and thermal storage systems, run from small household units to power plant and grid-scale technologies. What they aim to do is enable electricity to be released into the system when it is needed – so-called load shifting – rather than only when solar collectors or wind turbines are operating.

“Storage allows you to spread out the load and, if you can do that, you no longer need the big so-called base-load generators,” Moriarty says.
In thermal storage systems, renewable electricity or electricity purchased from the grid at off-peak rates is used to heat a material to a high temperature. 1414 Degrees uses molten silicon – an abundant and cheap element that is the main component of sand – that is heated to its melting point of 1414 degrees. The stored heat can then be used at a later time to generate electricity – using turbines – that is fed back into the grid. It can also release heat to be used in district heating systems for hot water or space heating.
The company has developed 10MW or 200MW systems, which can store heat for up to two weeks, although they are designed to be able to constantly charge and discharge according to demand. Unlike batteries, which have a finite number of charge/discharge cycles, the molten silicon can be used indefinitely and can be recycled when the units reach the end of their 20-year service life.
Other thermal storage systems take heat directly from the sun to heat storage materials. In these systems, concentrating solar collectors – rather than photovoltaic cells – are used to heat a liquid that can then heat a storage medium. Pilot scale facilities in Jemalong and Lake Cargelligo, both in central west NSW, use molten salt or graphite, respectively, to store heat.
According to Prof Frank Bruno, leader of the Thermal Energy Storage Group at the University of South Australia, one of the advantages of thermal storage is the ability to operate at high temperatures, unlike batteries, whose components suffer once temperatures go above about 50 degrees.
The other advantage is price. “Storing energy as thermal energy is much cheaper that battery storage,” says Bruno, although photovoltaic power plants currently out compete concentrated solar collectors.
The Australian Solar Thermal Research Initiative, of which Bruno is a member, is trying to bring the cost of concentrated solar collectors down, which would make integrated solar thermal storage systems more price competitive overall.
Battery makers are concentrating on trying to solve some of the key limitations of lithium ion batteries. One of those is the scant supply of raw materials required to make them, a supply that is unlikely to meet future energy storage demands, according to Prof Thomas Maschmeyer, co-founder of the University of Sydney spin-off company Gelion.
Gelion batteries use zinc and bromide, elements with more stable and abundant supplies than the lithium and cobalt of lithium ion batteries. Unlike lithium ion batteries, which will become more costly as demand for raw materials outstrips supply, the price of Gelion’s batteries will only decrease with increased production scales.
Gelion’s technology is based on a tweak of zinc/bromide chemistry – which is already used in Redflow batteries – that means the battery operates with a gel rather than a liquid. The resulting batteries look and work much like a lithium ion battery, but with greater heat tolerance. Gelion is currently raising funds to get their prototype into commercial production.
While there’s currently no front-runner to replace lithium ion batteries, according to those working across the range of storage devices available, there will be plenty of options ranging from household electricity storage, to grid-level systems like that proposed for South Australia.
“The market’s big enough and the needs are varied,” says Moriarty, so “there’s a place for all of them.”

Links

• Elon Musk, meet Port Augusta: four renewable energy projects ready to go
• Hazelwood's closure shows industry and government must plan ahead for climate change
• There is no gas crisis in Australia, but there is an attack on our natural assets
• The CommBank contradiction: support for cricket and fossil fuels

Geothermal: A Technology That Blows Hot And Cold In Sydney's Booming West

Fairfax - Peter Hannam

A Sydney housing estate is streets ahead when it comes to energy efficiency.

Fairwater is a new geo-thermal cooled mini-suburb near Blacktown. Photo: Wolter Peeters

During the peak of last summer's heat, an energy experiment the size of a mini suburb involving hundreds of new homes in western Sydney was under way.
With temperatures reaching 45 degrees for three days in a row, residents of the Fairwater estate going up at Blacktown relied on pipes to pump excessive heat as much as 90 metres under their homes to stay cool.
The geothermal technology itself is not revolutionary but Fairwater is the first housing estate to introduce it at scale in Australia.
Working much like modern airconditioners that can warm and cool, the Australian-made heat pumps use the temperature difference between the air and the ground to extract or reject heat.
Since the temperature below that area of Sydney's west barely budges from about 22 degrees all year round, the earth can serve as a heat dump during summer or a source of warmth in winter. The challenge is to make it at least as efficient as standard products on the market.
A $1 million drill, more commonly found on a mining site, drills a simple hole before any of the other construction work begins on the homes. Later, a copper loop containing refrigerant is added, with developers Frasers Property promising energy savings of as much as 60 per cent compared with regular airconditioning.
"We're hoping it will exceed that total [saving]," Ray Baksmati, the Fairwater development director, said. "The payback is about five years."
The extra engineering required adds about $3000-$5000 to costs to houses ranging from about $650,000 to more than $1 million. Geothermal costs for two-bedroom houses are lower because pipes only go down 60 metres through the mudstone compared with 90 metres for four-bedders.

Mini suburb cooled by geothermal technology
Homes in Blacktown's Fairwater estate rely on pipes to pump excessive heat deep underground to stay cool.

Mr Baksmati said Frasers worked for more than four years with QPS Geothermal, the drillers, and local airconditioner maker Actron Air to hone the process. The developer is now doing "real life testing" to see how systems performed.

Early response
A straw poll by Fairfax Media earlier this month found experiences ran hot and cold.

Fairwater construction manager Adam Chymiak with the rig that drills the geothermal pipelines. Photo: Wolter Peeters

Sid and Nimarta Banga said they were "mostly positively exuberant" since moving into Fairwater before summer's height. Their electricity bill came in at $260 for about eight weeks.
"You can't even feel like the airconditioning is working" because it's so quiet, Mr Banga said, adding "it works really quickly".

Fairwater residents have mixed views of the success of geothermal so far. Photo: Peter Hannam

Around the corner, Manvinder and Deepti Verma were also glad their three-month electricity bill came in at $450 for their four-bedroom house. "We were expecting a lot more," Ms Verma said.
The geothermal unit "should pay for itself in three or four years," Mr Verma said, adding that "very few people know about this system".

Fairwater development residents Sid and Nimarta Banga in front of their new home. Photo: Wolter Peeters

The equipment, though, has not been without glitches, with a portion of the Vermas' street tripping for several days. The fault left them – and their 15 month-old child – without cooling for two "unhappy" nights and a day during the heat peak.
Marc Crook, who rents in another street, is not happy, either. His summer's power bill came to $1385 and the system struggled so much to keep his house cool he resorted to spraying water on the coolant pipes to try to cool them.
"They really don't cope at all" once the mercury climbs above the low-30s, he said. "We'd be lucky to get it 24 degrees inside" even with the thermostat turned down to 16 degrees.
Mr Crook, who works in the boiler industry, said it stood to reason that "the harder and further you have to pump something, the more heat you're going to generate at the pump", reducing efficiency and effectiveness.

'Great achievement'
Adam Chymiak, Fairwater's construction manager, said that while there may be teething troubles at individual sites the overall outcome was "a great achievement".
The energy efficiency of the homes, which include fans in most rooms and LED lightning, meant the estate "lessened the demand on the overall grid" especially at peak times, he said. Fairwater is also the first community in NSW to be awarded a 6 Star Green Star Rating for sustainability.
Fairwater is planning to monitor and make public the performance of the geothermal systems, Mr Baksmati said.
Graham Morrison, an emeritus professor at the University of NSW said that geothermal could be an attractive option provided it delivered the promised energy savings: "Sixty per cent is quite OK – technically, it's close to the average of competing products."
Frasers is examining rolling out geothermal at its Edmondson estate near Liverpool, and says other developers are looking at the technology for their large sites too.
Professor Morrison said geothermal may work better for cooler climates, such as Melbourne, where heating is a bigger part of the annual energy bill. "Generally, the colder the climate is worse for solar [energy] but better for heat pumps," he said.
For Nimarta Banga, the benefit of installing geothermal in new homes may be that residents of a whole community start with lower energy use that may otherwise have been the case – whether they are aware of it or not.
"For us, it was a blanket package," she said. "No one will pay out of their pocket for [geothermal]."

'Living building'
Frasers Property is involved in another pioneering venture, the $115 million Burwood Brickwoods project in Melbourne's east.
The centrepiece of the mixed retail and housing project over 20.5 hectares on a former industrial site is the shopping centre. The developers are seeking the first "Living Building" certificate issued for a retailer by the International Living Future Institute.
The US-based group, which has certified about 360 projects worldwide, demands projects achieve at least net-zero energy, waste and water, and avoid a range of harmful "red-listed" materials from lead and cadmium to chemicals that don't break down in the environment.
Frasers will aim to generate 105 per cent of the energy used by the site, deploying as much as 3 megawatts of solar panels and batteries to meet its own needs and to export to neighbours or recharge customers' electric cars. Geothermal technology is not being considered as part of the project.
A 2000-square-metre farm, the largest of its kind in Australia, will supply vegetables and even poultry from within the retail site.
"It's called a challenge for a reason," Amanda Sturgeon, chief executive of the institute, said.
Peri Macdonald, ‎executive general manager for retail at Frasers, said meeting the building's ambitious sustainability goals will boost the retail portion's cost by about $12 million to $60 million.
"It's really going to push the envelope," Mr Macdonald said, adding the extra outlay is worthwhile because shoppers would be expected to linger longer – and spend more – in the more sustainable setting.
Tenants, such as Woolworths, have indicated a willingness to meet the higher energy and other standards.
"We don't expect it will change the tenant mix," Mr Macdonald said.

Links

• The Australian invention that could shrink your power bill
• For the first time on record, human-caused climate change has rerouted an entire river
• Solar-powered device pulls drinking water straight out of thin air
• Back-to-back bleaching covers two-thirds of the Great Barrier Reef
• Climate challenges line up in Australia's front and back yards
• Debbie does more damage - this time to insurers' profits
• Climate's threat to Australia's defences
• NSW added to insurance catastrophe declaration as waters rise

Humans On The Verge Of Causing Earth’s Fastest Climate Change In 50m Years

The Guardian - Dana Nuccitelli

Humans are changing Earth’s climate at an alarmingly fast rate

As climate scientist Wallace Broecker once said, “The climate system is an angry beast, and we are poking at it with sticks.” Photograph: Alamy

A new study published in Nature Communications looks at changes in solar activity and carbon dioxide levels over the past 420 million years. The authors found that on our current path, by mid-century humans will be causing the fastest climate change in approximately 50 million years, and if we burn all available fossil fuels, we’ll cause the fastest change in the entire 420 million year record.

Changes in atmospheric carbon dioxide and in the combined solar and carbon dioxide forcing over the past 420 million years. Illustration: Foster et al. (2017); Nature Communications.

The study relates to a scientific conundrum known as the “faint young sun paradox” – that early in Earth’s history, solar output was 70% less intense than it is today, and yet the planet was warm enough to have a liquid ocean. A stronger greenhouse effect due to higher carbon dioxide levels in the atmosphere may be one explanation.
Over time, solar output has grown stronger, and atmospheric carbon dioxide levels have fallen due to an effect known as “weathering” of rocks and an increase in plant life. The authors of this study found that over the past 420 million years, the slow heating of the sun and slow decline of the greenhouse effect have roughly offset each other, leading to a fairly stable long-term global climate.

Changes in the solar and carbon dioxide forcings over the past 420 million years. Illustration: Foster et al. (2017); Nature Communications.

In particular, as shown in the first chart above, Earth’s climate has been fairly stable over the past several million years. The wiggles in the blue line represent transitions in and out of ice ages, due to wobbles in the Earth’s orbit around the sun, amplified by changes in the amount of carbon dioxide in the atmosphere (these are known as Milankovich cycles).
The bottom frame in the chart shows the change in forcing (global energy imbalance) caused by the combination of changes in solar activity and the greenhouse effect. When the line is flat, the Earth’s energy balance is stable, and thus so is its climate. When there’s a steep change, something is upsetting that balance and causing a rapid climate change. The five colored lines toward the end of the chart show potential pathways we’ll follow, depending on how much fossil fuels humans burn over the coming decades.

In every case the line is already quite steep due to the hundreds of billions of tons of carbon pollution humans have dumped into the atmosphere thus far. The size of the global energy imbalance we’ve caused is already on par with those previous blue wiggles – Earth’s ice age transitions. If we keep burning lots of fossil fuels, we could soon cause higher carbon dioxide levels and faster climate change than the Earth has seen in 50 million years. If we burn all available fossil fuel reserves (the black “Wink12k” line), we’ll see faster climate change than in the entire 420 million year record.
It’s an alarming proposition. Climate deniers will often argue against taking action to curb carbon pollution because climate changed naturally in the past and carbon dioxide levels were higher in the past. One Republican congressman repeated these talking points in the latest House “Science” committee hearing. While both arguments are technically true, they miss several important points.
First, the rate at which we’re currently causing climate change is alarmingly fast – much faster than in most natural climate change events. Second, similar past rapid climate changes have caused mass extinction events. Third, the sun’s cooler past helped keep temperatures lower.
As renowned climate scientist Wallace Broecker once said, “The climate system is an angry beast, and we are poking at it with sticks.”

Denial101x lecture by Peter Jacobs.

As this new study shows, our poking sticks are getting bigger and bigger, and we’re poking the beast faster and faster. Meanwhile, climate deniers are egging us on because the beast has been angered in the past, and we’re not sure just how soon it will decide to maul us.

Links

• Future climate forcing potentially without precedent in the last 420 million years
• Earth is warming 50x faster than when it comes out of an ice age
• New study shows worrisome signs for Greenland ice
• New study links carbon pollution to extreme weather
• Inconceivable! The latest theatrical House 'Science' committee hearing
• Scientists understood the climate 150 years ago better than the EPA head today