Dear EarthTalk: What exactly are hydrofoils and why are environmental advocates so bullish on them revolutionizing the shipping industry? -- John C., Elizabeth, NJ
The shipping industry emits around three percent of the world’s greenhouse gas emissions annually, which is a comparable figure to that of the widely known airline industry’s footprint. Looking at how to make the shipping industry, and maritime transport, more sustainable is accordingly a key concern for environmental leaders around the globe. Hydrofoils are not a new concept, but electric ones may be a promising new innovation for the future of sustainable maritime travel, and the field is developing fast.
December 2022 saw the advent of the world’s fastest and most long-range electric ferry to date in Stockholm, Sweden, in the form of the Candela P-12 shuttle. Like all hydrofoils, this public transportation shuttle was built with a wing-like structure underneath itself that functions much like the airfoil seen on airplanes: As the official Candela press release states, “The hydrofoil technology means that the boat is lifted on wings that ’fly’ underwater, eliminating water resistance from pushing the hull through water. The hydrofoils reduce energy consumption by 80 percent compared to conventional ships.” This new combination of technology makes electric hydrofoils both faster than diesel-powered ships and cheaper to operate due to less stringent energy demands.
The wide-spread implementation of electric hydrofoil technology has not yet occurred. However, Stockholm’s KTH Royal Institute of Technology asserts that the inclusion of electric hydrofoils or similar technologies could potentially reduce the shipping industry’s emissions by 97.5 percent compared to the emissions of standard diesel-fueled ships. Furthermore, the very nature of the construction of these light-weight electric hydrofoils requires less material, overall minimizing the emissions of an electric hydrofoil throughout its lifetime.
In the face of rising global temperatures, and a projected increase in global greenhouse gas emissions, hydrofoils are necessary additions to the maritime industry if it hopes to reach the International Maritime Organisation’s goal of cutting carbon emissions by 40 percent by 2030. Beyond that, these ships also serve in the interest of efficiency, particularly since their lighter designs and inability to produce a wake mean that they are oftentimes faster than standard diesel boats: For example, the implementation of an electric hydrofoil has cut down one commuting route in Stockholm from 55 minutes to only 25.
The original concept of a hydrofoil has existed for decades, but electric hydrofoils are the “new kid on the block” focused on growing sustainable practices for the future. These boats’ low carbon footprint, lower operating costs and ability for more efficient transportation make them an interesting new opportunity for investment, and for a future that will require more environmentally-focused decisionmaking.
CONTACTS: Hydrofoil Basics, lancet.mit.edu/decavitator/Basics.html; Electric hydrofoil boats beat diesel boats for climate sustainability, kth.se/en/om/nyheter/centrala-nyheter/elektriska-barplansfartyg-klimatsmartare-an-dieselfartyg-1.1212858.
Dear EarthTalk: You hear a lot about shark sightings and attacks nowadays; does this mean that sharks are more abundant than ever and doing well overall—or the opposite? -- R.W., Welfleet, MA
It’s tough to accurately document shark sightings, but shark attacks are documented every year. There are two classifications of shark bites: provoked and unprovoked. Provoked bites occur after a person has initiated interaction with the shark, like attempting to touch or feed it. But, according to Gavin Naylor, director of the Florida Program for Shark Research, “Unprovoked bites give us significantly more insight into the biology and behavior of sharks. Changing the environment such that sharks are drawn to the area in search of their natural food source might prompt them to bite humans when they otherwise wouldn’t.”
Globally, unprovoked attacks in 2022 were 57. In 2021, there were 73. During the pandemic, many beaches shut down, but looking at the years preceding 2020, we can more accurately deduce changes in shark attack frequency. Using data from The University of Florida’s International Shark Attack File, the average number of annual unprovoked attacks from 2015 to 2019 was 79.4. Comparing this to 2022, it can be seen that the frequency of shark attacks has not risen significantly, if at all, in the past few years.
In spite of this, due to increasing ocean temperatures sharks are more inclined to travel into coastal waters where tourist activity is common. According to the National Oceanic and Atmospheric Administration, these waters are typically cooler than waters offshore. Warmer waters have higher concentrations of chlorophyll which attracts plankton growth. Many species of fish, rays and crabs feed on plankton. As ocean temperatures rise, northern and coastal waters grow warmer, attracting plankton, fish and other shark bait prey. As a result, sharks are more attracted to these regions than before.
Although the number of unprovoked shark attacks around the world has not increased, regions along the United States’ East Coast have seen upticks in shark incidents. In 2022, there were eight shark attacks in New York after three consecutive years of zero cases. In 2021, Florida experienced 28 shark attacks following a three-year-average of 17.67 annual incidents. Because of these increases, there may be more media coverage on shark attacks, leading people to believe that there are more sharks overall.
Though shark sightings may be becoming more frequent, shark numbers are dwindling. Many shark species are struggling in their native coral reefs and marine ecosystems. According to the journal Science, “Five of the most common reef shark species have experienced a decline of up to 73 percent.” In addition, The Washington Post states that “a third of all sharks, rays and related species are at risk of going extinct.” As a result, scientists are concerned that species lower on the food chain will overpopulate without the presence of sharks as natural predators.
Humans are responsible for many factors that may be causing a decline in shark populations. Overfishing deprives sharks of one of their primary food sources. Millions of sharks get entangled in fishing nets and longlines ever year. Plus, some 73 million sharks are killed for the shark fin and meat industry.
CONTACTS: The ocean phenomenon that's bringing sharks closer to shore, wral.com/story/the-ocean-phenomenon-that-s-bringing-sharks-closer-to-shore/20394126/; Widespread diversity deficits of coral reef sharks and rays, science.org/doi/10.1126/science.ade4884.
Dear EarthTalk: What exactly is “climate migration” and is it already happening? –B.T., via email
As discussions of the climate crisis begin to shift from future tense to present, ‘climate migration’ has become a growing concern. But what is it? The question is stickier than one might think. By its simplest definition, the phrase refers to the voluntary or involuntary movement of people from one place to another due to adverse ecological conditions, usually caused by global warming. Conditions can include natural disasters, gradual desertification, rising sea levels or crop-destroying insect migration, to name a few.
And therein lies the stickiness. For one, how can we be certain that adverse environmental conditions have been caused by climate change? To be certain, we would have to refer to the relatively new science of extreme event attribution, which is often inconclusive. Then, to call someone a ‘climate migrant’, the climatic conditions would have to be the principal motivation for their upheaval. Most often, it is a mixture of things that cause a person to pull up roots and move, and environmental factors are hard to separate from the rest: Climate change can also increase poverty, crime and political instability.
Another legally important issue is the term ‘migrant’. If the new turbulence of the environment is what forces people to move, wouldn’t it be best to call them climate ‘refugees’? That way the upheaved population would have greater protection, like access to legal services and planned relocation, although at the moment, the Refugee Act of 1951 does not cover climate displacement. The importance of definition and terminology is pivotal when it comes to the law, as well as recognition from host countries. Calling them refugees instead of migrants will, as the Council on Foreign Relations has said, “also be a signal from wealthier countries, which are most responsible for planet-warming greenhouse gas emissions, that there is a global responsibility to help those harmed by climate change.”
And the situation could hardly be more urgent. The UN High Commissioner for Refugees has determined that natural disasters alone force an annual average of 21.5 million people from their homes across the globe. In one study conducted by The New York Times, ProPublica and the Pulitzer Center, an extreme scenario could see “more than 30 million migrants [...] head toward the U.S. border over the course of the next 30 years.” Climate displacement has begun, and will only increase with the coming years.
The statistics are dire, and the consequences potentially catastrophic, but host countries have the opportunity to twist the best out of a bad situation. Climate displacement could fix economic problems associated with aging populations, and fill holes in the job market. Gaia Vince of The Guardian predicts that “cities from Munich to Buffalo will begin competing with each other to attract migrants.” So, yes, climate migration is happening now, and will increase with the warming and ecological disasters coming our way. Legal protection and clearer definitions are needed, but it's not all gloom. Climate migrants don’t only spell disaster, they also spell opportunity for those countries wise enough to see it.
CONTACTS: The century of climate migration: why we need to plan for the great upheaval, theguardian.com/news/2022/aug/18/century-climate-crisis-migration-why-we-need-plan-great-upheaval; Climate Change Is Fueling Migration. Do Climate Migrants Have Legal Protections? cfr.org/in-brief/climate-change-fueling-migration-do-climate-migrants-have-legal-protections; Show Me The Proof: Is Climate Change Definitively Causing Extreme Weather? emagazine.com/show-me-the-proof-is-climate-change-definitively-causing-extreme-weather/.
Dear EarthTalk: Are some of the newfangled entrance restriction tactics to reduce overcrowding at U.S. national parks having the desired effect? -- P. Smith, Provo, UT
With each passing day we grow more aware of our environment and its beauty. The U.S. has seen this newfound appreciation in the form of a high influx in visitors to national parks across the country. In the past year, visitors to U.S. national parks have increased by five percent—and since 1976, visitation has increased overall by some 75 percent. In 2022, two of the busiest national parks—Yellowstone and Yosemite—began to require reservations for entry for the first time in the history of the National Park Service (NPS). Increased awareness of our natural world is wonderful, but overcrowding creates detrimental effects, from the songbirds in the trees to the employees at the parking lot.
Environmental luminary John Muir once said, “The mountains are calling and I must go.” And now Americans are heeding this call like never before. To wit, some 312 million trips were made to national parks in the last year, with 12 parks breaking previous attendance numbers. Concentrated in tight weekend windows and school breaks, this trend has overwhelmed these tranquil sanctuaries of nature.
Making matters worse is that national parks weren’t initially developed to accommodate massive crowds. Combine the narrow roads, limited parking and lack of public transport with an impatient mob of visitors waiting to get their share of nature and you come up with a generous serving of chaos.
Yosemite National Park’s experimentation with requiring reservations in order to pass through the gates did help reduce Yosemite’s notorious overcrowding as much as rangers didn’t like turning people away. Zion National Park now disallows cars beyond the visitor center parking lot just inside the park gates. Visitors instead now rely on an efficient shuttle bus system which moves everyone right along between stops and hiking trailheads throughout the park’s main artery. Zion also offers visitors options like renting e-bikes and e-scooters for those who would rather skip the shuttle bus.
Arches National Park has implemented a timed-entry program that may be the secret sauce to figuring out overcrowding. Through the first three months of 2023, visitor numbers were down when compared to the two previous years. Innovative solutions like driverless shuttles and other sustainable technologies will only improve with time. It’s been a long journey for our parks over the last few years, but rays of optimism shine through the trees. While our parks aren’t exactly back to their peaceful, serene states yet, they sure are on the right trail back.
CONTACTS: Arches National Park may have found a magic bullet for overcrowding. Could it work at other parks? sltrib.com/sports/2023/05/07/arches-national-park-visitors-will/; A Visit to the National Park of the Future: Innovative transportation and emerging mobility to maximize sustainability and visitor experience, nps.gov/articles/000/a-visit-to-the-national-park-of-the-future-innovative-transportation-and-emerging-mobility-to-maximize-sustainability-and-visitor-experience.htm.
Dear EarthTalk: Are carbon capture technologies pie in the sky or really feasible as a global warming mitigation technique? -- Paul C., Scranton, PA
The short answer is ... we’ll see. To understand how to remove carbon dioxide (CO2) from our atmosphere, it is important to first look at how it gets there and why it's a problem in the first place.
Human activities are the dominant contributor to CO2 emissions through fossil fuel burning, electricity consumption and transportation. According to NASA, humans have caused increased CO2 concentrations by half since the 18th century, resulting in a 1.8°F temperature increase. This may seem insignificant, but the consequences are becoming more and more apparent, so scientists are going all out to figure out ways to limit potentially irreversible effects moving forward. Various emission reduction strategies are being put in play to help stave off the worst effects of global warming.
One of the most promising is so-called “carbon capture and storage” (CCS). Technologies that prevent carbon from entering the atmosphere by storing it have been around since the mid-1970s, but only recently have they scaled up to meet the demands of larger industrial settings. There are three steps to CCS: capturing, transporting and storing. First, CO2 is separated from other gasses that are released during industrial processes. Next, the CO2 is transferred through pipelines where it is then stored and often repurposed. Currently, there are 80 facilities in the process of implementing CCS, and 16 that have already done so. Its removal efficiency is targeted at 90 percent, with some able to reach 95-99 percent.
CCS is definitely a feasible method for removing CO2 from the atmosphere. Most carbon emissions come directly from a facility; the biggest advantage of CCS is its ability to prevent CO2 from escaping right from the source. The International Energy Agency estimates that CCS is capable of removing up to 20 percent of CO2 from industrial facilities. Also, other greenhouse gasses like nitric oxide and sulfur dioxide can also be sequestered. The CO2 that is captured can also be utilized for the creation of other commercial products like concrete and polymers. Geologically stored CO2 can be repurposed to collect geothermal heat, meaning geothermal energy can be extracted sustainably.
While this does sound like a perfect solution to our problems, there are some potential pitfalls. Although CCS does have high efficiency, the 90 percent of CO2 being removed isn’t enough, considering where we are with emissions now. With the race to develop maximum removal CCS projects, the costs increase greatly as well. According to the Global CCS Institute, the 26 plants created as of 2021 have only removed 0.1 percent of emissions, meaning that for this technology to be suitable, it would have to be applied in every industrial facility, globally—right now. So we have a situation where the costs outweigh the benefits, and due to its unpromising results“ …there’s no way it can actually improve to be better than replacing coal or gas with wind or solar directly,” says Stanford’s Mark Jacobson. “The latter will always be better, no matter what, in terms of the social cost.”
Most environmental advocates agree that focusing on renewables is the best course of action to reduce our greenhouse gas emissions. But CCS nevertheless remains a viable weapon in the arsenal of climate change fighters. With the various technologies advancing, it will play an especially important role as a bridge to a sustainable future for the planet.
CONTACTS: Global CCS Institute, https://www.globalccsinstitute.com/; Mark Z. Jacobson, https://web.stanford.edu/group/efmh/jacobson/.
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