Bioluminescence — otherwise known as “nature’s light” — is heat-free and great for medical, military and myriad other pollution-free applications. Credit: Joshua Lambus, FlickrCC.

Dear EarthTalk: Is there any way we could harness the light from bioluminescent organisms for everyday lighting and other practical purposes? — M. Wilson, Framingham, MA

Bioluminescence — defined by Merriam-Webster as “the emission of light from living organisms (such as fireflies, dinoflagellates, and bacteria) as the result of internal, typically oxidative chemical reactions” — is one of the wonders of nature that just about any of us can witness.

While a few organisms can produce bioluminescent light outside of the oceans (think fireflies), most of the bioluminescence going on is in saltwater. In fact, the vast majority of bioluminescent organisms evolved in order to provide light in deep sea marine ecosystems — either to light up prey or as a warning against predators — far below sunlight’s reach into the water column.

What exactly causes bioluminescence? Other sources of light (the sun, fire, light bulbs) generate energy from heat, whereas bioluminescent light comes from energy released in a chemical reaction: When two organic chemicals, luciferin and luciferase, combine, they release light-based energy as they oxidize.

While the general process is the same across all bioluminescent organisms, the color of the light in each situation depends on the chemical structures of the different life forms involved. Fireflies most commonly light up as green or yellow — and sometimes red — while most of the bioluminescence under water comes through as blue-green or green light.

Humans have been putting natural bioluminescence to work for a while — 19th century coal miners would trap fireflies in jars and use them as safety lights (instead of open-flame candles or lanterns that could cause an explosion). But nowadays researchers are hard at work synthesizing the chemical reactions behind bioluminescence for a range of modern-day applications.

Harnessing bioluminescence to help cure disease is a big focus of some biomedical research companies, given the promise of using heat-free organic light to detect metastasizing cancer cells, stem cells, viruses or bacteria within living tissue. The military also has big hopes for utilizing the chemical reactions of bioluminescence to create light that won’t trigger the heat-seeking sensory equipment of the enemy — whether on land, at sea or in the sky.

Some other practical applications of bioluminescence, as recently highlighted by Popular Mechanics, include an effort to splice genes from bioluminescent organisms into trees that would light up when the sun sets (as an all-natural alternative to street lights), using bioluminescent bacterium to highlight contaminants in drinking water supplies, and genetically modifying crop seeds to grow fruits and vegetables that could signal their need for more water or other inputs by glowing accordingly.

While none of these “technologies” is yet ready for mainstream implementation, it’s good to know that the future looks bright even if we run out of fossil fuels to power our traditional light bulbs.

Contacts: “The emerging use of bioluminescence in medical research,” bit.ly/bioluminescence-med-research; “6 Bright Ideas for Bioluminescence Tech,” bit.ly/6-bright-ideas-bioluminescence.


This graphic shows the United Kingdom as represented in a Global Climate Model (GCM), a Regional Climate Model (RCM) and actual observations. Credit: Met Office.
Dear EarthTalk: What are so-called regional climate models and why do we need them, given that we already have pretty decent global climate models? — Rich W., Seattle, WA

Scientists (and economists and business people) love to create models to help predict future outcomes as a way to direct planning and preparedness efforts. Climatologists specifically love to create models of how the planet and its various natural systems and cycles will react with the input of way too many greenhouse gas emissions in the atmosphere. Climate science has come a long way since its early days a few decades back, but most of what we think will happen regarding global warming comes from global climate models–that is, predictions based on lots of empirical data about how much global average temperature is expected to rise and by when.

“Global climate models (GCMs) simulate the interactions between the atmosphere, ocean and land to project future climate, based on assumptions about future emissions of greenhouse gases,” reports the Climate Impacts Group at the University of Washington (UW).

According to ClimatePrediction.net, a volunteer computing and climate modeling project out of the UK’s University of Oxford, global climate models (GCMs) are designed to calculate what the climate is doing (in terms of wind, temperature, humidity, etc.) at a number of discrete points on the Earth’s surface as well as in the atmosphere and out at sea. The points are then laid out in a grid covering the planet’s surface. The more points at play, the finer the resolution (and accuracy) of the model.

Nowadays climate researchers are applying what they have learned thus far to look in more detail on a regional basis, especially given that climate change has not only large-scale but also local consequences. These so-called regional climate models (RCMs) work by magnifying the resolution of GCMs in a small, limited area of interest, typically within a 3,000 square mile radius. Only by creating and analyzing RCMs can we assess the influence of myriad fixed geographic conditions and other local factors such as land height, land use, lakes, sea breeze, mountain ranges and localized weather patterns on climate impacts for a particular metropolitan area, state or country.

“For the practical planning of local issues such as water resources or flood defenses, countries require information on a much more local scale than GCMs are able to provide,” adds ClimatePrediction.net. “Regional models provide one solution to this problem.”

UW’s Climate Impacts Group has been able to leverage its expertise in global and now regional climate modeling to do groundbreaking research into the likelihood of things like floods in the Pacific Northwest, expected moisture flux convergence and ensuing drought in the Southwest, and, even further afield, projected climate change and impacts in Southeast Asia. The analytical techniques being pioneered at UW are being shared with researchers around the world with the hope that more and more scientists will start to run RCMs in their own regions to help planners plan and improve people’s lives despite the warming climate.

GCMs and RCMs are both important tools in figuring out how to cope with the effects of climate change, whether a worst case scenario is borne out or something not quite so cataclysmic.

Contacts: ClimatePrediction.net, ClimatePrediction.net; UW Climate Impacts Group, cig.uw.edu.


Carbon Engineering has proven at its Canadian pilot plant in Squamish, British Columbia that it can suck greenhouse gases out of the air through so-called Direct Air Capture (DAC) and process them into liquid fuels at a cost nearly as cheap as producing fossil fuels.
Dear EarthTalk: If we already know how to capture carbon dioxide (CO2) and turn it into fuel, why aren’t we doing more of it? — M.N. Daly, Springfield, MA

With recent measurements detecting the highest levels of atmospheric CO2 in human history — and experts warning we have less than a dozen years to turn around our profligate emissions to avoid cataclysmic changes — the time is nigh to start ratcheting down our carbon footprints. One solution that seems obvious, but has been slow to get out of the starting gate, is scrubbing large amounts of CO2 from the air and recycling it as a feedstock to produce carbon-neutral fuels to power our machines.

We have known how to capture CO2 from the air at a large scale since the 1950s, but it wasn’t until the late 1990s that environmentalists started looking to so-called “Direct Air Capture” (DAC) as one of a suite of tools at our disposal for dealing with the greenhouse effect. Since then, researchers have been scrambling to come up with the most efficient ways to capture CO2.

Massachusetts-based start-up Carbon Engineering formed in 2011 in an effort to produce and eventually commercialize DAC technology that can use captured CO2 to make fuel at costs competitive with producing conventional fossil fuels. After several years of research and development and implementation of its technologies at a pilot plant in British Columbia, the company has been able to get the costs of capturing CO2 down to ~$100/ton — six times less than previous models predicted was possible.

But it’s what happens next that has environmental advocates jazzed. Carbon Engineering’s solar-powered electrolyzer splits water into hydrogen and oxygen, and then combines the hydrogen with previously captured CO2 to make carbon-neutral gasoline, diesel or even jet fuel. Assuming a $100/ton cost for capturing atmospheric CO2, the company can produce these eco-friendly fuels for about $1/liter, which is only marginally more expensive than their fossil-fuel counterparts. The hope is that costs will come down to below fossil fuels as demand grows and facilities scale up. Also, as more states follow California’s lead in requiring increasingly significant portions of their fuel mixes to come from “low-carbon” sources, demand for these green alternative fuels will rise and prices will likely drop even more.

R&D like this isn’t limited to the U.S. Spain’s SUN-to-LIQUID project uses unique solar concentration technologies that combine sunlight with oxygen and atmospheric CO2 to get three times as much energy out of the sun’s rays as existing solar “reactors.” The resulting “synthesis fuel” combines hydrogen and carbon monoxide and could be used to power vehicles or any type of engine equipped to deal with it.

And a team of Swiss and Norwegian scientists wants to put such technologies to use on millions of solar-powered floating islands at sea that could suck CO2 out of the air and turn it into fuel without taking up any land or bothering human neighbors. Such a plan may seem far-fetched, but we need to be open to new ideas if we are going to turn the tide on climate change before we reach the dreaded “point of no return.”

Contacts: “Atmospheric CO2 hits record high in May 2019,” earthsky.org/earth/atmospheric-co2-record-high-may-2019; “Renewable transportation fuels from water and carbon dioxide,” https://phys.org/news/2019-06-renewable-fuels-carbon-dioxide.html; “A Process for Capturing CO2 from the Atmosphere,” www.cell.com/joule/fulltext/S2542-4351(18)30225-3; “11 million floating solar farms could eliminate carbon emissions from transport,” www.chemistryworld.com/news/11-million-floating-solar-farms-could-eliminate-carbon-emissions-from-transport-/3010580.article


Tea tree oil, witch hazel & milk of magnesia are just a few of the all-natural treatments you can use to make pimples go away and keep problem acne at bay. Credit: Kjerstin Michaela, Pixabay.
Dear EarthTalk: I suffer from occasional acne but am loathe to treat it with harsh chemicals. Do you know of all-natural ways to get rid of pimples or prevent them altogether? — J. W., Miami, FL

Acne — when sebum from oil glands under the skin clogs pores causing small bacterial infections that lead to swelling and discomfort — isn’t just a temporary annoyance during our teenage years; it plagues many of us throughout our adult lives, as well. Some 85 percent of Americans are prone to at least occasional break-outs or worse. But common over-the-counter treatments–most containing either benzoyl peroxide or salicylic acid–can irritate the skin, eyes and lungs and are also linked to more serious health problems. The U.S. Food & Drug Administration (FDA) warns that the use of these over-the-counter topicals “can cause rare but serious and potentially life-threatening allergic reactions or severe irritation.”

Most of the top-selling brands incorporate benzoyl peroxide or salicylic acid in their acne treatments, but the only way to know for sure what’s inside any given product is to consult its label. Even better, do some research online before you buy. The Environmental Working Group’s free online Skin Deep database lists ingredients — and more importantly, the health and environmental threats — of over 120,000 personal care products, including more than 2,000 different acne treatments now or recently available on store shelves.

As far as alternative treatments go, tea tree oil, distilled from the leaves of Australia’s Melaleuca plant, seems to be a favorite. Studies have shown it to be equally as effective as benzoyl peroxide in reducing both the number of acne lesions and their severity. Likewise, Witch Hazel has similarly positive effects for most who try it, although there hasn’t been any scientific research to back that up yet.

According to National Geographic, dabbing a pasty mixture of powdered nutmeg and honey onto a problem pimple and leaving it there for 20 minutes can help unclog pores. Another trick is to soak a chamomile tea bag in cold water, squeeze it out, then hold it onto a pimple for 30 seconds. Icing a new pimple can also help reduce swelling and discomfort and shorten its lifespan. And smearing a little milk of magnesia on your face at bedtime can help prevent break-outs to begin with.

Healthline’s Kayla McDonnell suggests dabbing zits with apple cider vinegar or witch hazel or applying a honey/cinnamon mask. Her other tips for pimple remediation include regular exfoliation, taking a zinc and/or fish oil supplement, eating a low glycemic load diet, cutting back on dairy, reducing stress and exercising regularly.

If your acne is more severe, it might be worth consulting a dermatologist who can recommend prescription-strength treatments that can work with your body chemistry to limit the production of sebum in the first place. But drying, irritation and/or other side effects can ensue from these doctor-prescribed treatments as well, so be sure to let your doctor know so he or she can adjust the dosage or treatment plan.

Contacts: Skin Deep, www.ewg.org/skindeep; FDA’s “Topical Acne Products Can Cause Dangerous Side Effects,” bit.ly/acne-risks; “13 Powerful Home Remedies for Acne,” www.healthline.com/nutrition/13-acne-remedies; “The efficacy of 5% topical tea tree oil gel in mild to moderate acne vulgaris: a randomized, double-blind placebo-controlled study,” www.ncbi.nlm.nih.gov/pubmed/17314442.

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