Based on his name and the picture in the article, I assume the author is Dutch. We don’t have the distinction between underpasses and tunnels in our language and just call everything ‘tunnel’. It may have to do with the country being so flat that there are no mountains to tunnel through.
I can only think of a single real bicycle/pedestrian tunnel, which is the Maastunnel in Rotterdam. Incidentally it is also one of the oldest tunnels in the country. It was recently renovated and is actually really pleasant to cycle through, because motorised traffic uses a separate tunnel tube.
As for turns in underpasses, at complex junctions or infrastructural elements it may be tempting to just make a small bend so that the underpass is cheaper to build or easier to fit in to the environment. Take these crossroads for example: https://goo.gl/maps/21Yqj89WwyiiuZfD9. If you look closely you will see a bicycle tunnel going underneath from the southwest to the northeast. This important connection for the residents southwest of the shopping center is relatively long and has a slight bend. This makes it feel dark and unsafe to the people who use it.
A better design can be found at this roundabout: https://goo.gl/maps/TXuFjXj85huufc7m6. Because the middle section is open, all of the individual underpasses are short and there is a lot of daylight, making cycling there safer and more pleasant.
Here in Italy (where we have lots of mountains and conversely tunnels) the distiction between tunnel and underpass (or overpass) is neat, we also have (though not extremely common) distinctions betweeen different kinds of tunnels (Galleria):
Overpass is called "viaduct" in Dutch, though a multi-lane overpass is often colloquially called a tunnel. We do have tunnel-like structures for what technically are overpasses, eg.: bike path next to a river; major multilane road crosses river+bikepath; resulting structure for bike path is a tunnel (Dommeltunneltje in Eindhoven), though doesn't go underground.
I think it has to do with design. They wanted to make the two top rows have the same amount of lights. Using 6 would mean one row of 6 lights and one of 4. 5^2 is the smallest square that provides enough values to fit 24 hours.
A lot of these seem to be ambiguous. "Let's have lunch sometime" followed by some form of actual commitment (phone number, "does next friday work for you", etc) might mean what they literally said. But if it's used to end the conversation... Yeah, you're not getting lunch.
When a tree dies that CO2 will mostly just be released into the air again. Planting trees is a measure to slow the immediate effects of fossil fuel usage, but not a long term solution. At some point you’ll run out of space for new trees.
It’s like fixing a leaky pipe by adding sponges. Sure, they’ll soak up the water and are cheap, but eventually you will run out of space for new sponges and have to pay for a plumber.
It's more like fixing a leaky pipe by adding a patch that will last for centuries, that can pollinate itself and produce additional patches in the future, and that can be removed and used as a building material for a new house.
"and that can be removed and used as a building material for a new house."
I'm all for building wooden houses. But I can also imagine the amount of work (=> energy consumption) needed to convert theses trees we need to plant to "offset emissions" as new houses.
Transport the workers, feed the machines to chop the trees, the machines to transport the wood, to run the lumber-mill, to transport to the construction site etc. Unfortunately for now we still have: feeding machines => energy consumption => emissions
We can argue that this energy would have been needed anyway to build new houses. However I find it dangerous to couple a carbon reduction strategy to a substantial amount of an activity involving machines (construction). Are we going to need the amount of houses at the scale of the amount of trees we need to plant? In all parts of the world concerned (we don't want to move trees across the world anymore..)?
Unless you have a system in place to take responsibility from seed to logging to long term encapsulation I'll be highly skeptical of that.
What's to say it wont be slashed and burnt to make room for agriculture? What's to say the surplus of timber wont decrease the price and cause less trees to be planted elsewhere?
It's still sponges, not patches. They absorb the water, and you have to manage them. If you don't actively store them, the water will leak out. If you do actively store them and then hand off storage to someone else, the water will leak out when that someone stops paying attention.
The way to sequester carbon with trees is to cut them down when they're grown, and bury them somewhere where there's no air and no one will touch them for thousands of years, or otherwise store them in perpetuity while preventing decay or burning.
Turning them into biochar is a slightly simpler proposal. Biochar is stable for a pretty long time. But of course the process of unburning all the coal we burned so far is not very viable.
It's not an infinitely long term solution but it's a solution that buys us at the very least dozens, if not hundreds of years before we run out of space. Because no solution is ever infinite, given that the Sun isn't, it doesn't make sense to consider something that will potentially work for a hundred years as a non long term solution. By the time that solution stops being long term, we'll have far more advanced options to buy us another century of time.
That's all the CO2 lifecycle is in nature - Oil / Gas are basically large sponges which absorbed Carbon a long time ago, and were buried.
It's not impossible that we could grow a huge number of trees, and bury the resulting wood in a mountain-side to offset burning coal - but the amount of wood we'd need to bury might be prohibitively large.
While this is a good development, hydrogen based planes would not be climate neutral. Unfortunately a large and often overlooked part of planes’ climate impact stems not from their carbon emissions but from the water vapor they produce [1]. Contrails reflect heat and thereby contribute to global warming. If we want planes to actually be harmless to the climate, we should probably be looking at electric planes.
Seems there's some debate about that and the article didn't actually cite any resources to back it up. According to the end of this National Science Foundation article [1], it depends on the type of cloud. Contrails are maybe analogous to cirrus clouds, which block more thermal energy from the ground than they reflect back into space.
I read that AC installation companies have been getting a lot of business in the past few weeks, and anecdotally I've heard from local businesses looking to install it as well. So I'd say yes, it'll definitely become more common.
We generate a lot of heat, but so does the sun by shining on half of the earth's surface. That should not be a problem however, since it goes back into space in the form of infrared beams. The natural greenhouse effect obstructs just enough of those beams to keep our planet at a stable temperature that life has had plenty of time to adjust to. Now that the greenhouse effect has been artificially enhanced by adding lots of greenhouse gases to the atmosphere, more infrared beams (from the sun, but probably also some from human activity) are kept in the atmosphere and so it warms. So ultimately, the sun is just vastly more powerful than human activity, and any excess heat would be emitted into space if it weren't for the artificially raised greenhouse gas concentrations in the atmosphere.
Well, there are six intercity trains per direction each hour to Amsterdam Central, four to Amsterdam South (will be upped to six in a few years), and up to four commuting services. So you could even say there’s a train every 4.3 minutes.
It looks like the main problems were problems with HVAC (which wouldn't be a problem in California and probably could be more easily solved with modern building materials) and the ugliness of it. Everybody in the Bay Area would surely hate a version of the Skyrise Terrace in their city but it could be a good idea if someone could buy a large parking structure and retrofit it for mobile home utilities.
With just 16km, this is not by any stretch going to be the world's second-longest tunnel, just the world's second-longest road tunnel. The longest tunnels are rail tunnels, which measure up to 57km (Gotthard base tunnel), and if you count subway tunnels the longest is Guangzhou metro line 3 with 60km. (https://en.wikipedia.org/wiki/List_of_long_tunnels_by_type#U...)
And they are building a bypass of 2.5 miles but will take total of 8 years. All so they can fix major leaks in the current aqueduct. Fascinating project.
I can only think of a single real bicycle/pedestrian tunnel, which is the Maastunnel in Rotterdam. Incidentally it is also one of the oldest tunnels in the country. It was recently renovated and is actually really pleasant to cycle through, because motorised traffic uses a separate tunnel tube.
As for turns in underpasses, at complex junctions or infrastructural elements it may be tempting to just make a small bend so that the underpass is cheaper to build or easier to fit in to the environment. Take these crossroads for example: https://goo.gl/maps/21Yqj89WwyiiuZfD9. If you look closely you will see a bicycle tunnel going underneath from the southwest to the northeast. This important connection for the residents southwest of the shopping center is relatively long and has a slight bend. This makes it feel dark and unsafe to the people who use it.
A better design can be found at this roundabout: https://goo.gl/maps/TXuFjXj85huufc7m6. Because the middle section is open, all of the individual underpasses are short and there is a lot of daylight, making cycling there safer and more pleasant.