EarthTalk® | November 2015


Dear EarthTalk: Do scientists have any idea why so many whales are dying in the Gulf of Alaska lately? — Michelle DiCostanzo, New York, NY

Over the past four months, 33 large whales have been reported dead in the Western Gulf of Alaska, which encompasses the areas around Kodiak Island, Afognak Island, Chirikof Island, the Semidi Islands and the southern shoreline of the Alaska Peninsula. The significant die-off of whales has been declared an Unusual Mortality Event (UME) by the National Oceanic and Atmospheric Administration (NOAA), marking the first large whale UME ever in Alaska.

The majority of the deceased humpback, fin and gray whales have been found moderately to severely decomposed, and scientists have only been able to obtain samples thus far from one fin whale. Alaskan citizens have been instructed to call the Alaska Marine Mammal Stranding Network hotline immediately if a stranded or dead whale is spotted to ensure the fastest response possible by trained experts.

“Large whale UMEs are the most difficult UMEs to deal with, principally because the animals are floating and rarely beached and we have a difficult time getting to the carcasses to actually examine them,” says Dr. Teri Rowles, coordinator of the NOAA Fisheries Marine Mammal Health and Stranding Program. “The most critical thing for this UME, given it is large whales, is our ability to get to the animals, document them, and if possible perform sample collections either at sea or on the beach if they are stranded. It is critical that the public and mariners report large whale mortalities or animals that they see in distress as soon as possible so that the Network can either document, access or track the carcasses.”

Exposure to harmful algae blooms (HAB) is NOAA’s leading theory for the cause of the surge in whale deaths. While the organization has collected some disparate samples of phytoplankton in the Gulf of Alaska that they determined could possibly produce biotoxins, there is no conclusive data currently associating the whale deaths to HAB, and the fin whale sample tested negative for HAB biotoxins.

“Even though the one sample we tested was negative, it was not the most appropriate sample to collect and test for biotoxins. We can’t rule it out based on the results we have right now,” Rowles adds. “It’s my understanding that sea surface water and air temperatures in the Gulf of Alaska have been high, and that always concerns us because that means there’s probably a change in overall pathogen exposure — possibly HABs and other factors.”

Claims that the UME is linked to the Fukushima nuclear reactor meltdown or the Navy-led “Northern Edge” military training exercises conducted in the Gulf of Alaska this past June have been dismissed due to lack of evidence. Muscle tissue from the fin whale sampled was sent to the University of Alaska Fairbanks for cesium analysis, and the preliminary results did not suggest any unusual exposure to manmade radiation. As the investigation continues, NOAA will be publishing updated information pertaining to the UME on their website as it becomes available; however, the investigation could take months or even years to complete.

“It takes a fair amount of time to pull data together even if the event is over, and a lot of deliberation and analyses have to happen in order to determine what’s going on,” Rowles added. “It could be quite a period of time before we actually have an answer, if indeed we end up with a definitive answer for this UME.”

CONTACT: NOAA Fisheries, Photo above: Scientists worry that the wondrous spectacle of humpback whales breaching in the Gulf of Alaska might become more infrequent. Credit: PhotoSpin

Solar desalination
Solar desalination plant on the island of Funafuti in the Tuvalu islands. Credit: Nick Hobgood, FlickrCC
Dear EarthTalk: What exactly is solar desalination and how can it help an increasingly thirsty world?– Maryann Dell’Amore, Howard, MN

Solar desalination is a technique used to remove salt from water via a specially designed still that uses solar energy to boil seawater and capture the resulting steam, which is in turn cooled and condensed into pristine freshwater. Salt and other impurities are left behind in the still.

Less than 1 percent of the world’s desalination is powered by renewable energy sources today, but that could all change soon if companies like California-based WaterFX have anything to say about it. Its Aqua4 “concentrated solar still” uses a concentrated solar thermal collector to compress heat, create steam and distill water at 30 times the efficiency of natural evaporation. It can produce 65,000 gallons of freshwater per day — and it can desalinate a wide range of water sources, not just seawater.

To wit, the company will start employing solar desalination to treat some 1.6 billion gallons of salt-laden irrigation drainage from California’s drought-stricken, agriculturally-rich Central Valley next year. Crops extract nearly pure water from soil, leaving behind salt and other potentially toxic minerals like selenium that naturally occur in the water. These excess minerals must be drained from the soil, or crop productivity plunges. By treating this drainage, WaterFX can prevent about 15 percent of farmland in California from being retired every year to make room for storage for untreated drainage water. It will also prevent the drainage from contaminating fresh waterways and endangering wildlife. According to California’s State Water Resources Control Board, approximately 9,493 miles of rivers and streams and some 513,130 acres of lakes and reservoirs are listed as being impaired by irrigated agricultural water.

“If we don’t start removing the salts now, at least 10 percent of all current farmland in production in California will have to be retired, and in many scenarios this number could be up to 30 to 40 percent, especially on the west side of the Valley where the salinity is very high,” says WaterFX’s Matthew Stuber. “Water in the drainage areas will contaminate groundwater and natural surface waterways at an accelerated pace, eventually polluting sources of drinking water and the natural environment. Once that is released into the environment, you severely damage the natural habitat and wildlife.”

Another large-scale solar desalination project is currently under construction in Saudi Arabia and scheduled for completion in early 2017. The plant is slated to produce 60,000 cubic meters of water per day for Al Khafji City in North Eastern Saudi Arabia, ensuring a constant water supply to the arid region throughout the year. According to Abengoa, the Spanish renewable energy company building the pioneering facility, the incorporation of solar would significantly reduce operating costs, as Saudi Arabia currently burns 1.5 million barrels of oil per day at its desalination plants, which provide 50-70 percent of its drinking water. Total desalination demand in Saudi Arabia and neighboring countries is expected to reach 110 million cubic meters a day by 2030.

With freshwater supplies at a premium already in many parts of the world as a result of climate change, there has never been a better time for solar desalination to come of age. Whether or not this emerging technology can go mainstream sooner than later may mean the difference between a peaceful future and one wracked by conflict over access to ever-dwindling supplies of freshwater.

CONTACTS: WaterFX, ; California’s State Water Resources Control Board,; Abengoa,

greenhouse gas emissions
Whether to cap-and-trade or tax carbon emissions is still a hot topic of debate among environmentalists, economists, policymakers and politicians. Credit: Billy Wilson, FlickrCC
Dear EarthTalk: What’s the difference between a carbon tax and “cap-and-trade” system for reducing greenhouse gas emissions? — Marina Brown, New York, NY

Most of us can agree that reducing greenhouse gas emissions is a must, given the rapid warming of the planet; just how to do it best is another question entirely. The two leading market strategies are a carbon tax, whereby polluters are simply taxed for the carbon dioxide and other greenhouse gases they spew, and “cap-and-trade,” whereby government sets an overall cap on the amount of greenhouse gases that each industry or sector can emit without penalty and issues permits or allowances accordingly that companies can buy and sell to each other based on their own business and sustainability priorities. Each approach has been shown to effectively cut down emissions, but many nations are now weighing which way to go as they prepare to make new commitments as part of the potentially decisive international climate talks (COP21) coming up in Paris in December 2015.

Cap-and-trade allows affected businesses to choose how much pollution reduction they can tolerate and then leverage market forces to buy or sell allowances accordingly. Such systems effectively penalize polluters who exceed allowable limits (those who therefore must “buy” credits) while rewarding those who do not just meet emissions target levels but get down below them (the difference being what they can then “sell”). Cap-and-trade markets are designed to encourage flexibility in allowing companies to decide how they want to meet emissions reduction targets.

Of course, cap-and-trade isn’t a new concept. The first national cap-and-trade market limited emissions of sulfur dioxide and nitrogen oxide that were causing acid rain in 1990s. The European Union later launched the first major market in greenhouse gas emissions trading in 2005 in order to meet commitments made under the Kyoto Protocol, the first international treaty to limit carbon emissions. In North America, three regional carbon cap-and-trade plans have been in place since the mid-2000s (the Regional Greenhouse Gas Initiative, Midwest Greenhouse Gas Reduction Accord, and Western Climate Initiative), but there hasn’t been enough political will at the federal level yet to support a nationwide carbon emissions market.

Not everyone thinks cap-and-trade is the way to go to reduce emissions. Carbon tax proponents argue that cap-and-trade scenarios can cause unnecessary price volatility to energy prices, are overly complicated, and are easily manipulated by those that learn to game such systems to their advantage without reducing greenhouse gas output. “Carbon taxes will lend predictability to energy prices, whereas cap-and-trade systems will aggravate the price volatility that historically has discouraged investments in less carbon-intensive electricity generation, carbon-reducing energy efficiency and carbon-replacing renewable energy,” reports the Carbon Tax Center.

Critics counter, however, that it’s easier for companies to pass the costs of a carbon tax onto consumers by raising prices — and that lower income households bear a disproportionate amount of those economic costs. Perhaps the world’s biggest experiment in carbon taxation ended last year when Australians voted to repeal their carbon tax due to rising costs of living, saving the average household more than $500 a year. Meanwhile, a recent analysis of Norway’s carbon tax — the highest in the world on a percentage basis — found that emissions reductions there were negligible over the first decade of implementation.

While both systems have their pros and cons, either can be effective in reducing emissions if there is enough political will behind it. A key component to the upcoming COP21 Paris climate talks is flexibility in allowing participating nations to choose how they want to reduce emissions. Environmental leaders are keeping their fingers crossed that whether through cap-and-trade or taxation, the nations of the world will finally agree on enough greenhouse gas cuts to finally stem the still surging tide of global warming.

CONTACTS: COP21,; Carbon Tax Center,

All that concrete underfoot accounts for as much as 10 percent of greenhouse gas emissions globally. Credit: Tony Cyphert, FlickrCC
All that concrete underfoot accounts for as much as 10 percent of greenhouse gas emissions globally. Credit: Tony Cyphert, FlickrCC
Dear Earthtalk: I’ve heard that making and installing concrete takes a big toll on the environment. What’s being done to clean up this industry? — Jenn Chadwick, Washington, D.C.

The 20 billion tons of concrete produced around the world annually account for an estimated five to 10 percent of global carbon dioxide (CO2) emissions. Concrete is one of the most widely used materials in the world, and the energy-intensive process to create it is the third-largest source of planet warming CO2. According to a 2012 study from Scotland’s University of Aberdeen, making a ton of concrete releases about a ton of CO2 into the atmosphere. While the concrete industry has actually reduced its carbon emissions by a third over the last few decades, it still has a long way to go before becoming part of the solution to our collective climate woes.

Part of the reason concrete is so energy- and CO2-intensive to make is that it requires heating the mineral feedstock, alite, to 1,500 degrees Celsius to make it malleable. Researchers are working to develop mixtures using alternatives to alite that do not require such high temperatures during processing. The leading contender, belite, has a much lower temperature threshold while maintaining similar strength. But belite takes months to set completely, while alite sets in just a few hours. Concrete makers continue to tinker with the mix, as well as with other chemicals and additives, in search of greener alternatives to alite.

Dust pollution generated by concrete’s manufacture and disposal is another big concern. Quarrying entire mountainsides worth of rock for the aggregate that makes up the majority of concrete’s material sends massive amounts of rock dust into the atmosphere. The back end of concrete’s lifecycle is similar to the demolition of buildings, which emits large amounts of concrete dust into the air. New technologies that trap and reduce dust emissions are making inroads, but not nearly fast enough, say environmental leaders.

Another green trend among concrete makers is recycling in one form or another. According to the U.S. Environmental Protection Agency, some are using waste ash products from other industries to create an entirely new, greener concrete mix. Others are focusing on collecting concrete chunks from demolition sites and crushing them to re-use in new construction projects. Such efforts require less energy and less water and as a result can reduce the carbon footprint of manufacturing concrete significantly.

Of course, all that finished concrete around us not only inhibits biodiversity — wildlife doesn’t find paved-over areas particularly hospitable — it also leads to pollution, erosion and flooding as torrents of run-off can’t naturally percolate through soils as they make their way downstream. So-called permeable concrete seeks to address this issue by absorbing much more water than traditional concrete, slowing down and significantly reducing urban run-off. Yet another concern is that concrete absorbs much more heat than does soil, so cities are often significantly warmer than rural areas, exacerbating the greenhouse effect. One solution to this so-called “urban heat island effect” may be lighter-colored concrete, which has been shown to reflect up to 50 percent more light than its more traditional darker counterparts.

While there is much innovation afoot within the concrete industry, the vast majority of concrete produced still isn’t particularly green. Until some of these forward-thinking techniques and technologies become more mainstream, the pavement beneath our feet will continue to be a thorn in the side of those working to fight climate change and clean up our environment.


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