The world is only a few decades away from a major food crisis, according to a top scientist at the U.S. Agency for International Development.
“For the first time in human history, food production will be limited on a global scale by the availability of land, water and energy,” said Dr. Fred Davies, senior adviser for the agency’s bureau of food security. “Food issues could become as politically destabilising by 2050 as energy issues are today.”
Davies, who is also a Texas A&M AgriLife Regents Professor of Horticultural Sciences, addressed the North American Agricultural Journalists meeting in Washington, D.C. on the “monumental challenge of feeding the world.”
Global population will increase 30 percent to 9 billion people by mid-century. However, that would require a 70 percent increase in food production to meet demand from the rising middle classes, he said.
“But resource limitations will constrain global food systems,” Davies explained. “The increases currently projected for crop production from biotechnology, genetics, agronomics and horticulture will not be sufficient to meet food demand.”
The ability to discover new ways to keep pace with food demand has been curtailed by cutbacks in spending on research, he added.
“U.S. agricultural productivity has averaged less than 1.2 percent per year between 1990 and 2007,” he said. “More efficient technologies and crops will need to be developed — and equally important, better ways for applying these technologies locally for farmers — to address this challenge.”
When new technologies are developed, they often do not reach the small-scale farmer worldwide.
“A greater emphasis is needed in high-value horticultural crops,” he continued. “Those create jobs and economic opportunities for rural communities and enable more profitable, intense farming.”
Horticultural crops, Davies noted, are 50 percent of the farm-gate value of all crops produced in the U.S. He also made the connection between the consumption of fruits and vegetables and chronic disease prevention and pointed to research centres in the U.S. that are making links between farmers, biologists and chemists, grocers, health care practitioners and consumers. That connection, he suggested, will also be vital in the push to grow enough food to feed people in the coming decades.
"Agricultural productivity, food security, food safety, the environment, health, nutrition and obesity – they are all interconnected," Davies said. One in eight people worldwide, he said, already suffers from chronic undernourishment and 75 percent of the world's chronically poor are in mid-income nations such as China, India, Brazil and the Philippines.
"The perfect storm for horticulture and agriculture is also an opportunity," Davies added. "Consumer trends – such as views on quality, nutrition, production origin and safety – impact what foods we consume. Also, urban agriculture favours horticulture." For example, he said, the fastest growing segment of new farmers in California is female, non-Anglos, who are "intensively growing horticultural crops on small acreages."
The superior light-emitting properties of quantum dots can be applied to solar energy, helping to more efficiently harvest sunlight.
A house window that doubles as a solar panel could be on the horizon, thanks to recent work by Los Alamos National Laboratory researchers in collaboration with scientists from the University of Milano-Bicocca (UNIMIB), Italy. Their project demonstrates that superior light-emitting properties of quantum dots can be applied in solar energy by helping more efficiently harvest sunlight.
Quantum dots are ultra-small nanocrystals of semiconductor matter that are synthesized with nearly atomic precision. Their emission colour can be tuned by simply varying their dimensions. Colour tunability is combined with high emission efficiencies approaching 100%. These properties have recently become the basis of a new technology – quantum dot displays – employed, for example, in the newest generation of the Kindle Fire e-reader.
A luminescent solar concentrator (LSC) is a photon management device, representing a slab of transparent material that contains highly efficient emitters such as dye molecules or quantum dots. Sunlight absorbed in the slab is re-radiated at longer wavelengths and guided towards the slab edge equipped with a solar cell.
Quantum dot LSC devices under ultraviolet illumination.
Lead researcher Victor Klimov explained: “The LSC serves as a light-harvesting antenna – which concentrates solar radiation collected from a large area onto a much smaller solar cell – and this increases its power output.”
“LSCs are especially attractive because, in addition to gains in efficiency, they can enable new interesting concepts such as photovoltaic windows that can transform house facades into large-area energy generation units,” said his colleague, Sergio Brovelli.
To implement their concept, Los Alamos researchers created a series of cadmium selenide/cadmium sulfide (CdSe/CdS) quantum dots, which were then incorporated by the Italian team into large slabs of transparent polymer. The particles are tiny, only about 10 nanometres (nm) across. For comparison, human hairs are typically 50,000 nm wide.
Spectroscopic measurements indicated virtually no losses to re-absorption on distances of tens of centimetres. Tests using simulated solar radiation demonstrated high photon harvesting efficiencies of around 10% per absorbed photon – achievable in nearly transparent samples – perfectly suited for utilisation as photovoltaic windows.
These findings are published in Nature Photonics. According to a report earlier this year, the quantum dot and quantum dot display (QLED) markets are expected to see a 42-fold growth in the next five years, reaching $6.4 billion by 2019.
A new statistical analysis of temperature data since the year 1500 concludes "with confidence levels greater than 99%, and most likely greater than 99.9%" that recent global warming is not caused by natural factors and is man-made.
A new analysis of temperature data since 1500 all but rules out the possibility that global warming in the modern era (1880 — present) is just a natural fluctuation in the Earth’s climate. The study, led by Professor Shaun Lovejoy at McGill University, is published in the peer-reviewed scientific journal Climate Dynamics. It represents a new approach to the question of whether global warming in modern times has been caused by man-made emissions from the burning of fossil fuels. Rather than using complex computer models to estimate the effects of greenhouse-gas emissions, Lovejoy examines historical data to assess the competing hypothesis: that warming over the past century is due to natural, long-term variations in temperature.
“This study will be a blow to any remaining climate-change deniers,” Lovejoy comments. “Their two most convincing arguments – that the warming is natural in origin, and that the computer models are wrong – are either directly contradicted by this analysis, or simply do not apply to it.”
Lovejoy’s study applies statistical methodology to determine the probability that global warming since 1880 is due to natural variability. His conclusion: the natural warming hypothesis may be ruled out “with confidence levels greater than 99%, and most likely greater than 99.9%.”
To assess the natural variability before much human interference, the new study uses “multi-proxy climate reconstructions” developed by scientists in recent years to estimate historical temperatures, as well as fluctuation-analysis techniques from nonlinear geophysics. The climate reconstructions take into account a variety of gauges found in nature – such as tree rings, ice cores, and lake sediments. And the fluctuation-analysis techniques make it possible to understand the temperature variations over a wide range of time scales.
For the industrial era, Lovejoy uses carbon dioxide from the burning of fossil fuels as a proxy for all man-made climate influences – a simplification justified by the tight relationship between global economic activity and the emission of greenhouse gases and particulate pollution. “This allows the new approach to implicitly include the cooling effects of particulate pollution that are still poorly quantified in computer models,” he says.
While his new study makes no use of the huge computer models commonly used by scientists to estimate the magnitude of future climate change, Lovejoy’s findings effectively complement those of the International Panel on Climate Change (IPCC), he says. His study predicts, with 95% confidence, that a doubling of carbon dioxide levels in the atmosphere would cause the climate to warm by between 1.9 and 4.2 degrees Celsius. That range is more precise than – but in line with – the IPCC’s prediction that temperatures will rise by 1.5 to 4.5 degrees Celsius if CO2 concentrations double.
“We’ve had a fluctuation in average temperature that’s just huge since 1880 – on the order of about 0.9 degrees Celsius,” Lovejoy says. “This study shows that the odds of that being caused by natural fluctuations are less than one in a hundred and are likely to be less than one in a thousand.
“While the statistical rejection of a hypothesis can’t generally be used to conclude the truth of any specific alternative, in many cases – including this one – the rejection of one greatly enhances the credibility of the other.”
Nanotechnology startup company, StoreDot, has unveiled a ground-breaking battery capable of charging your smartphone and other devices in under 30 seconds.
At Microsoft’s Think Next symposium in Tel Aviv, StoreDot demonstrated the prototype of its ultra-fast-charge battery for the first time. This company specialises in technology that is inspired by natural processes. They have produced "nanodots" derived from bio-organic material that, due to their size, have both increased electrode capacitance and electrolyte performance. These nanodots – described as "stable, robust spheres" – have a diameter of just 2.1 nanometres and are made of chemically synthesized peptide molecules, short chains of amino acids that form the building blocks of proteins.
StoreDot’s bio-organic devices, which include smartphone displays, provide much more efficient power consumption, and are eco-friendly. While other nanodot and quantum-dot technologies currently in use are heavy metal based, and therefore toxic, StoreDot's are biocompatible and superior to all previous discoveries in the field. Using their method, the company is hoping to synthesize new nanomaterials for use in a wide variety of applications. Nano-crystals in memory chips, for example, could triple the speed of traditional flash memory, while image sensors could be five times more sensitive.
Furthermore, the nanodots are relatively inexpensive, as they originate naturally, and utilise a basic biological mechanism of self-assembly. They can be made from a vast range of bio-organic raw materials that are readily available and environmentally friendly.
The battery seen in the video above remains in the prototype stage, with a rather bulky form factor. However, the CEO of Storedot, Doron Myersdorf, says he is confident that a smaller version can be developed and on the market by 2017.
“The fast-charge battery is the result of our focus on commercialising the materials we have discovered," he explained. "We’re particularly pleased that this innovative nanotechnology, inspired by nature, not only changes the rules of mobile device capabilities, but is also environmentally-friendly.”
In the landmark case of Australia v. Japan, the International Court of Justice (ICJ) in The Hague today ruled that Japan's JARPA II whaling program is not for scientific purposes and has ordered all permits to be revoked.
A major victory was achieved by conservationists today as the ICJ announced their binding decision on Australia v. Japan – ruling by a vote of 12 to 4 that Japan's Antarctic whaling program is not scientific research as defined under the International Whaling Commission regulations. The Court orders that Japan "revoke any extant authorization, permit or licence to kill, take or treat whales in relation to JARPA II, and refrain from granting any further permits."
Like its predecessor, the JARPA II program takes place in the Southern Ocean. Starting in 2005 and continuing to the present day, objectives have included monitoring the Antarctic ecosystem, modeling competition between whale species, recording changes in stock structure and improving future management of whales. However, the research methodology and value has come under intense scrutiny, as it has been argued that non-lethal alternatives are possible and that Japan's research is commercial whaling in disguise.
"With today's ruling, the ICJ has taken a fair and just stance on the right side of history by protecting the whales of the Southern Ocean Whale Sanctuary and the vital marine ecosystem of Antarctica, a decision that impacts the international community and future generations," said Captain Alex Cornelissen of Sea Shepherd Global. "Though Japan's unrelenting harpoons have continued to drive many species of whales toward extinction, Sea Shepherd is hopeful that in the wake of the ICJ's ruling, it is whaling that will be driven into the pages of the history books."
"Despite the moratorium on commercial whaling, Japan has continued to claim the lives of thousands of the gentle giants of the sea in a place that should be their safe haven," said Sea Shepherd Founder, Captain Paul Watson. "Sea Shepherd and I, along with millions of concerned people around the world, certainly hope that Japan will honor this ruling by the international court and leave the whales in peace."
At a public meeting in Los Angeles in December 2013, the Ambassador from Japan to the U.S., Kenichiro Sasae, said that his country would abide by the ICJ ruling. Sea Shepherd Global – the only organisation to directly intervene against Japan's illegal whaling – has ships prepared to return to the Southern Ocean, should Japan choose to ignore this decision.
New observations of northeast Greenland – once considered the most stable part of the ice sheet – have shown it is actually losing vast amounts of ice. This suggests that future sea-level estimates need revising upwards.
Map courtesy of Ohio State University
The last remaining stable area of the Greenland ice sheet – the second largest in the world, after the Antarctic ice sheet – is no longer stable, according to research by an international team of scientists. The finding, which is likely to boost estimates of global sea level rise in the future, appears in the journal Nature Climate Change.
The study focuses on ice loss due to a major retreat of an outlet glacier, connected to a long "river" of ice – known as an ice stream – that drains from the interior of the ice sheet. The Zachariae ice stream retreated by around 20 km (12.4 mi) over the last decade, the researchers concluded. For comparison, the Jakobshavn ice stream in southwest Greenland, among the fastest moving glaciers, has retreated 35 km (21.7 mi) over the last 150 years.
Ice streams drain ice basins, the same way the Amazon River drains the very large Amazon water basin. Zachariae is the largest ice stream in a drainage basin that covers 16 percent of the Greenland ice sheet – an area twice as large as the one drained by Jakobshavn.
This paper represents the latest finding from GNET – the GPS network in Greenland that measures ice loss by weighing the ice sheet as it presses down on the bedrock.
"Northeast Greenland is very cold. It used to be considered the last stable part of the Greenland ice sheet," explained GNET lead investigator Michael Bevis, from Ohio State University. "This study shows that ice loss in the northeast is now accelerating. So, now it seems that all of the margins of the Greenland ice sheet are unstable."
Historically, Zachariae drained slowly, since it had to fight its way through a bay choked with floating ice debris. Now that the ice is retreating, the ice barrier in the bay is reduced, allowing the glacier to speed up and draw down the ice mass from the entire basin.
A major outlet glacier in northeast Greenland, disintegrating into the ocean. Credit: Finn Bo Madsen/Ohio State University.
"This suggests a positive feedback mechanism, whereby retreat of the outlet glacier – in part due to warming of the air and in part due to glacier dynamics – leads to increased dynamic loss of ice upstream. This suggests that Greenland's contribution to global sea level rise may be even higher in the future," said Bevis, who is also the Ohio Eminent Scholar in Geodynamics and professor of earth sciences at Ohio State.
Study leader, Shfaqat Khan, a senior researcher at the National Space Institute at the Technical University of Denmark, said that the finding is cause for concern.
"The fact that the mass loss of the Greenland Ice Sheet has generally increased over the last decades is well known," Khan said, "but the increasing contribution from the northeastern part of the ice sheet is new and very surprising."
GNET uses the Earth's natural "elasticity" to measure the mass of the ice sheet. As previous Ohio State studies revealed, ice weighs down bedrock, and when the ice melts away, the bedrock rises measurably in response. More than 50 stations along Greenland's coast weigh the ice sheet, like a giant bathroom scale.
Khan and his colleagues combined GNET data with ice thickness measurements by four different satellites: the Airborne Topographic Mapper (ATM), the Ice, Cloud and Land Elevation Satellite (ICESat), and the Land, Vegetation and Ice Sensor (LVIS) from NASA; and the Environmental Satellite (ENVISAT) from the European Space Agency.
They found that the northeast Greenland ice sheet lost about 10 billion tons of ice per year from April 2003 to April 2012. According to previous measurements and aerial photographs, the northeast Greenland ice sheet margin appeared to be stable for 25 years – until 2003. Around that time, a string of especially warm summers triggered increased melting and calving events, which have continued to the present day. An example of a calving event is seen here in the recent documentary Chasing Ice:
Faster ice flow in this region is particularly troubling, Khan said, because the northeast ice stream stretches over 600 km (about 373 miles) – deep into the centre of the ice sheet, where it connects with the heart of Greenland's ice reservoir: "This implies that changes at the margin can affect the mass balance deep in the centre of the ice sheet. Furthermore, due to the huge size of the northeast Greenland ice stream, it has the potential of significantly changing the total mass balance of the ice sheet in the near future."
Bevis agrees: "The fact that this ice loss is associated with a major ice stream that channels ice from deep in the interior of the ice sheet adds some additional concern about what might happen."
The Greenland ice sheet is among the largest contributors to global sea level rise, accounting for 0.5 millimetres of the current total of 3.2 millimetres annually. A recent survey by the Vision Prize – which provides impartial and independent polling of experts on important scientific issues – found a majority of expert respondents believe that future sea levels will likely be at the upper end of the IPCC's projections.
Solar power production in California hit a new record of 4,093 megawatts on Saturday 8th March – more than double its capacity in 2013 and quadruple the level seen in 2012.
California has one of the largest and most modern power grids in the world. The new record for solar is enough to power about 3 million homes. Meanwhile, combining wind resources of 5,890MW and solar resources of 5,231MW, the two forms of energy now offer a maximum potential of 11,121MW. All renewables (including geothermal) can provide 15,000MW.
"This shows that California is making remarkable progress in not only getting new resources approved and connected to the grid, but making meaningful contributions in keeping the lights on as well," says Steve Berberich, President and CEO of the California Independent System Operator (ISO). "The milestones illustrate that we are well into a new era when clean, renewable energy is shouldering its share of our electricity needs — and that is exciting."
California remains the largest producer of solar power in the nation, while continuing to build a raft of huge new projects. The McCoy Solar Energy Project, for example, was approved yesterday and will provide 750MW of power, while several other plants of similar size have already begun construction. Clean energy will dominate the region's power supply by 2020, if trends continue. Only Texas surpasses California in terms of wind resources and California is among the top five states for adding wind capacity.
In March 2013, Lancaster in California became the first U.S. city to mandate the inclusion of solar panels on new homes, requiring that "every new housing development must average 1 kilowatt per house."
Last year, a study found that Pacific bluefin tuna populations had fallen by 96% from their original levels, due to decades of overfishing. International cuts were agreed to limit juvenile fish catches, but Japan concluded that these measures did not go far enough. Japan's Fisheries Agency has now responded by announcing a 50% reduction in catches from 2015, while urging other nations to do the same.
More than 4.4 million tons of tuna are being hauled from the world's oceans each year – much of which ends up as sushi, which is becoming ever more popular as a cuisine. This level of depletion is now unsustainable and could lead to the extinction of tuna in the near future, unless urgent action is taken. About 60% of the global catch is obtained from the Pacific region, conducted mostly by so-called "distant water" fleets from as far afield as Europe. Other species including skipjack, yellowfin and bigeye tuna are also severely threatened.
Japan's announcement could be an important step towards restoring tuna populations worldwide. Another solution that offers some hope is the rapid growth of aquaculture, which may actually surpass wild catch harvests by 2026. In the longer term, it might be possible to eliminate fish kills entirely – this could be achieved using a combination of 3D printing and/or synthetic fish food that is artificially "grown" via tissue engineering. If this were to happen, fish populations could eventually be restored to their pre-industrial levels. Scientists have already been making progress in this area, demonstrating the first laboratory-grown hamburger last year.
A series of giant walls – stretching up to 100 miles along the U.S. "Tornado Alley" – could prevent such disasters from happening in the future, according to physicists.
A scene from Judge Dredd (1995). Hollywood Pictures / Buena Vista Pictures.
The idea is vaguely reminiscent of Mega City One, a fictional city-state in the Judge Dredd universe. The outer walls of Mega City One spanned vast distances – protecting residents from potential weather or environmental disasters outside.
Now researchers believe a structure of similar appearance and scale might become a reality in the not-too-distant future. Running from east to west, several 1,000 ft (300 m) high walls – in Kansas, Louisiana, North Dakota, Oklahoma and Texas – could dampen the effects of tornadoes. In the American Midwest, these violent weather events are caused by intensive encounters between northbound warm air flows and southbound colder air flows. By deploying "great walls" at a number of strategic locations (determined by computer modelling), it might be possible to disrupt the formation of twisters and prevent them from gaining momentum.
The concept has been put forth by Prof Rongjia Tao of Temple University, Philadelphia and was discussed this week at the American Physical Society in Denver. Tao claims the project would cost about $16bn (£9.6bn), but in the long term would save many billions of dollars more in terms of protecting buildings and infrastructure. It could prove an especially useful adaptation measure when considering the rapid increase in disasters from climate change. The Moore tornado that struck Oklahoma last year was among the costliest tornadoes in U.S. history (adjusted for inflation), with peak winds of 210 mph (340 km/h) causing $2bn in damage, killing 25 people and injuring 400 others. Some meteorologists estimated that the energy released by the storm was over 600 times greater than the atomic bomb dropped on Hiroshima.
As evidence for his theory, Professor Tao has cited the flat plains of China, which are broken up by east-west hill ranges. Despite being only a few hundred metres high, these have a dampening effect on air currents, with only three tornadoes occurring in the region last year, compared to 803 in the U.S.
A similar effect is seen in parts of America, as Tao explains: "Washington County is a tornado hotspot. But just 60 miles (100 km) away is Gallatin County, where there is almost no risk. Why? Just look at the map – at Gallatin you have the Shawnee Hills."
Like the hills in China, these are only 200-250 m (650-820 ft) in height, but have a major influence on weather patterns. Computer models have already been demonstrated by Tao and his team. The next step is to build physical models for testing in wind tunnels. No government or environmental agencies have yet been contacted, but if this megaproject ever became a reality, he is confident it would be technically and financially viable. Rather than being eyesores – like the monolithic walls of Mega City One – they could also be designed in a visually attractive way.
"I spoke to some architects and they said it's possible," he added. "It would take a few years to finish the walls but we could build them in stages."
With self-sustaining gardens, this new eco-friendly skyscraper in Sri Lanka will give residents a sensation of ground-level living. The 46-storey tower is planned for completion in 2016.
Pictured here is Clear Point Residences, a new high-rise apartment complex in Kotte, Sri Lanka. The $100 million project – the first of its kind in the country – features an innovative design that is highly sustainable. This includes solar panels for electricity generation, planted facades, automated drip irrigation and water recycling systems.
These self-sustaining gardens provide cool and shady terraces, ensuring that no windows are exposed to direct sunlight, which therefore reduces the need for air conditioning units. They offer enhanced privacy and a tranquil environment that absorbs CO2, air and noise pollution. All of the apartments are cross-ventilated to provide further cooling. In addition to lowering energy consumption, the utility systems cut water usage from the grid by 45% – thanks to harvested rainwater, recycled bathroom water and on-site sewage treatment. Moreover, steps have been taken to allow the building to evolve in time with necessary additions from advancements in technology.
As designer Milroy Perera states: "Ultimately, the aim is to create a living space where you can not only feel at one with the environment, but actively contribute towards safeguarding and sustainable use of its resources. We are working very closely with our contractors Maga Engineering to enable the first self-sustaining building in Sri Lanka. The main focus of the apartment will be to provide an atmosphere and sentiment of ground-level living."
The 186 m (610 ft) structure will consist of 164 three bedroom apartments, four apartments per level, each of 2,300 ft2 with all internal spaces opening into planted terraces. The apartments are designed in a sleek and sophisticated manner. Construction of the tower is now underway and due for completion in early 2016, at which point it will become the world's tallest vertical garden – surpassing the 33-storey, 117 m (384 ft) One Central Park in Sydney, Australia. Given the environmental challenges the world faces, eco-towers like these could be fairly commonplace by 2050.
Despite claims of a recent slowdown in global mean temperature, the number of local temperature extremes has "dramatically and unequivocally increased in number and area", according to researchers at the University of New South Wales. This has also occurred despite the complete absence of a strong El Niño since 1998.
This image shows a time series of temperature anomalies for hot extremes over land (red) and global mean temperature (black, blue). The anomalies are computed with respect to the 1979-2012 time period. The time series are based on the ERA-Interim 95th percentile of the maximum temperature over land (Txp95_Land, red) and the global (ocean + land) mean temperature (Tm_Glob) in ERA-Interim (blue) and HadCRUT4 (black).
Extremely hot temperatures over land have dramatically and unequivocally increased in number and area despite claims that the rise in global average temperatures has slowed over the past 10 to 20 years during what some public commentators have called a global warming hiatus period.
Scientists from the University of New South Wales (UNSW) ARC Centre of Excellence for Climate System Science and international colleagues made the finding when they focused their research on the rise of temperatures at the extreme end of the spectrum, where impacts are felt the most.
“It quickly became clear, the 'hiatus' in global average temperatures did not stop the rise in the number, intensity and area of extremely hot days,” said one of the paper’s authors, Dr Lisa Alexander.
“Our research has found a steep upward tendency in the temperatures and number of extremely hot days over land and the area they impact, despite the complete absence of a strong El Niño since 1998.”
The researchers examined the extreme end of the temperature spectrum because this is where global warming impacts are expected to occur first and are most clearly felt. As Australians saw this summer and the last, extreme temperatures in inhabited areas have major impacts on society. The observations also show that extremely hot events are now affecting, on average, more than twice the area when compared to similar events 30 years ago.
To get their results, which are published in the journal Nature Climate Change, the researchers examined hot days starting from 1979. Temperatures of every day throughout the year were compared against temperatures on that exact same calendar day from 1979-2012. The hottest 10 per cent of all days over that period were classified as hot temperature extremes.
Globally, on average, regions normally expect around 36.5 extremely hot days in a year. The observations showed that during the period from 1997-2012, regions that experienced 10, 30 or 50 extremely hot days above this average saw the greatest upward trends in extreme hot days over time and the area they impacted. The consistently upward trend persisted right through the “hiatus” period from 1998-2012.
“Our analysis shows there has been no pause in the increase of warmest daily extremes over land and the most extreme of the extreme conditions are showing the largest change,” said Dr Markus Donat.
“Another interesting aspect of our research was that those regions that normally saw 50 or more excessive hot days in a year saw the greatest increases in land area impact and the frequency of hot days. In short, the hottest extremes got hotter and the events happened more often.”
While global annual average near-surface temperatures are a widely used measure of climate change, this latest research reinforces that they do not account for all aspects of the climate system. A stagnation in the increase of global annual mean temperatures, over a relatively short period of 10 to 20 years, does not imply that global warming has stopped. Other measures – such as extreme temperatures, ocean heat content and disappearance of land-based ice – all show continuous changes that are consistent with a warming world.
“It is important when we take global warming into account, that we use measures that are useful in determining the impacts on our society,” said Professor Sonia Seneviratne from ETH Zurich, who led the study while on sabbatical at the ARC Centre. “Global average temperatures are a useful measurement for researchers, but it is at the extremes where we will most likely find those impacts that directly affect all of our lives. Clearly, we are seeing more heat extremes over land more often as a result of enhanced greenhouse gas warming.”