Hello, fellow traveller. This is our weekly newsletter on all things environmental, where we highlight trends and solutions that are moving us to a more sustainable world. (Sign up here to get it in your inbox every Thursday.)

This week:

Organic waste is the (mushy) gift that keeps on giving

How cities can protect themselves from climate change

Which city has the biggest tree canopy?

Bitcoin vs. the environment

This scientist thinks organic garbage shouldn't be wasted

Canadian biotech entrepreneur Luna Yu is researching novel uses for organic waste. (Craig Chivers/CBC)

In the 17th century, a German alchemist named Hennig Brand had a dream — of extracting gold from urine. (They were similar in colour, after all.) He didn't succeed, but he did discover the element phosphorus.

Canadian biotechnology entrepreneur Luna Yu is on a similar quest. Her Toronto-based company, Genecis, aims to turn organic waste like apple cores, chicken bones and soiled tissues into valuable materials. I wrote about the company's work to turn kitchen waste into plastics for food packaging. But its ultimate goal is even more profitable products, such as cosmetics.

Right now, Yu says, green-binnables aren't reaching their full potential, "which is why organic waste is still getting sent to landfills."

Canadian municipalities do try to squeeze a little extra value out of the waste before composting by using anaerobic digesters to extract biogas (i.e. gases produced by the breakdown of organic matter without oxygen), which can be burned to generate heat and electricity. Yu interned at a company that did that, and she realized that turning waste into biogas is an "uneconomic way of dealing with it."

The trick is creating alternatives. Alchemists thought the key was a mythical tool called the philosopher's stone, which could turn lead into gold. The modern-day equivalent is bacteria, both natural and genetically modified, that can transform simple molecules into more complex chemicals.

Different bacteria can make different chemicals in different ways. To have as many options as possible, Yu got friends to collect bacteria from all over the world. For example, they'd put some lake water in a little vial while on vacation in places like Guatemala and sneak the microbes back to Canada. Since the incorporation of Genecis, all work has been conducted using non-pathogenic bacteria sourced locally. Yu hopes to expand and improve what the bacteria can do by genetically modifying them (a concept known as synthetic biology).

Genecis's first product will be premium compostable plastics called PHAs, which are used in things like medical devices. Yu says PHAs can generate seven times more revenue than biogas.

Next, they have their eye on ambroxides, which are pricey perfume ingredients that were originally found in the intestines of sperm whales but can now be made synthetically. Turning stinky green-bin waste into something that smells so amazing you'd wear it on a date - now, that would be real alchemy.

— Emily Chung

Climate change and cities: What are the major risks?

Big cities like Calgary need to find ways to mitigate flooding, among other effects of climate change. (Larry MacDougal/Canadian Press)

The effects of climate change — from torrential rains to massive forest fires — are not just obvious in southeast Asia or the southern U.S. They're being felt in Canadian cities. Nicole Mortillaro asked Blair Feltmate, head of the Intact Centre on Climate Adaptation at the University of Waterloo, what cities can do to reduce the risk of extensive damage.

BF: Relative to the most costly form of extreme weather risk within cities – which is basement flooding — as a top priority cities should implement programs that focus on home flood risk assessment. These programs would consist of properly trained people meeting with homeowners at their door, and over the course of a 10-minute conversation, provide the homeowner with basic guidance on 10 steps the homeowner could take around the outside of their property, and within the basement, that would lower their risk of basement flooding.

Relative to problems associated with freezing rain – which for example has proven to be repeatedly problematic in New Brunswick in recent years – within cities, tree-trimming programs should be deployed to prevent ice-laden branches from falling on hydro lines. In most cases within cities, it is not the ice on the lines that proves problematic, but rather ice-encrusted branches that fall onto electric wires.

Relative to forest fires affecting homes and communities in forested regions, there is one answer — large-scale deployment of the FireSmart program. The FireSmart program – which was originally developed in Alberta, and has since benefited from the expertise of all provinces and territories — focuses on pre-emptive measures to limit the probability of a fire entering a town or city, and subsequently lowering the chances that homes will burn when in proximity to fire.

Examples of the FireSmart program in action include establishing a fire-break around a town (e.g., by removing vegetation around the periphery of a town), and at the level of the house, installing fireproof shingles, siding and porches. Also, shrubs should not be planted, and wood should not be stored, within several metres of a house.

This interview has been edited and condensed.

The Big Picture: The cities with the most tree cover

Trees: what's not to love? They suck up carbon and beautify the outdoors. Bottom line: We need more of them. The World Economic Forum collaborated with MIT's Senseable Lab to create Treepedia, which shows which major cities provide the most tree coverage of the ground when viewed from above. As you'll see below, the Top 10 include two in Canada. (Toronto is 14th.)

Hot and bothered: Provocative ideas from around the web

The U.S. midterm elections are next week and few candidates for office have put the environment front and centre. This piece argues that rather than try to convince politicians to care, the point should be to galvanize more environmentalists to vote.

General Motors is pushing the Trump administration to institute a 50-state plan to speed up electric vehicle (EV) adoption . How? By extending federal tax credits for EV purchases and mandating 25 per cent of the fleets of the big car companies are electric or hybrid vehicles.

We try to keep this newsletter positive, but there's no way to sugarcoat a new study from the World Wildlife Fund, which says 60 per cent of vertebrates have been wiped out since 1970.

But! Swiss philanthropist Hansjorg Wyss has announced he is donating $1 billion to step up land and ocean conservation efforts around the world. Sehr großartig, Herr Wyss!

How bad is bitcoin for the environment?

The allure of bitcoin has been darkened somewhat by its carbon footprint. (Dan Kitwood/Getty Images)

Bitcoin has been a subject of fascination in recent years as an alternative currency and an investment opportunity — as well as a growing strain on the planet's resources.

The cryptocurrency is based on blockchain, a complicated computing process that maintains a ledger of transactions. Creating new bitcoins (through a process known as "mining") requires a lot of server power, which in turn requires a lot of electricity. In an interview with our colleagues at CBC Radio's Spark last year, an economist in Holland pointed out that authenticating a single bitcoin transaction takes as much electricity as running a washing machine 200 times. Yowza.

And bitcoin is only becoming more popular.

A new study by the journal Nature Climate Change said that bitcoin alone could produce enough carbon emissions to push global warming above 2 C in less than three decades.

This has alarmed environmentalists (while giving bitcoin skeptics another reason to hate it). But some analysts have said the analysis is flawed — and that bitcoin may not in fact roast the planet.

The study points out, for example, that much of the bitcoin being mined relies on coal power in Asia. But as the news site Axios writes, the study's projections "assume that the fuel types used to generate electricity will remain the same as they are today." And that is unlikely to be the case.

For one thing, more operators of bitcoin farms could be prodded to move to less carbon-intensive regions. While coal and natural gas are still major sources of energy in many countries, rapid growth in renewables such as wind and solar worldwide suggests that if bitcoin continues to be a going concern, its carbon footprint is likely to become a less significant issue.

— Andre Mayer

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Editor: Andre Mayer | Logo design: Sködt McNalty