[HN Gopher] Botanical gardens can cool city air by an average of...
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Botanical gardens can cool city air by an average of 5degC
Author : Brajeshwar
Score : 295 points
Date : 2024-02-27 13:59 UTC (9 hours ago)
(HTM) web link (newatlas.com)
(TXT) w3m dump (newatlas.com)
| Solvency wrote:
| Now, if only we can do something about the absolutely endemic
| heat desert effect we've created by caking our country in massive
| black asphalt parking lots and 6-lane freeways.
|
| Nope, can't examine that. Parking lots are peak human design. The
| most logical design solution for our species.
| o_____________o wrote:
| Obligatory mention of Not Just Bikes:
|
| https://www.youtube.com/@NotJustBikes/videos
| 01HNNWZ0MV43FF wrote:
| "The road to hell is paved with asphalt" saw this here on HN
| not long ago - https://devonzuegel.com/the-road-to-hell-is-
| paved-with-aspha...
|
| They mention less heat as one of the multiple benefits of
| pavers / bricks.
|
| I used to dislike them by default - "They're bumpy". They're
| not bumpy. There's a shopping center in my town, and even a new
| Taco Bell, that use pavers for their parking lot, and I can't
| even notice.
|
| We could probably do pavers for new parking lots and keep
| asphalt / concrete for heavy-duty stuff like interstates and
| roads over 30 MPH and not lose much except the up-front cost of
| pavers. (But hey if Taco Bell thinks they're worth it...)
| apercu wrote:
| "Bumpiness" could be climate related - I've spent a lot of
| time in the upper midwest US and Canada, the freeze/thaw
| cycles mean things move in the earth.
| Filligree wrote:
| If you've got freeze/thaw cycles, then your asphalt roads
| will be bumpy as well. Trust me on that one.
| kwhitefoot wrote:
| Only if the foundations are bad and the road surface is
| not rated for the axle load of the vehicles that drive on
| it. I live in Norway where it is hovering around freezing
| just now. The only places where this affects the road is
| where water has penetrated the foundations in such a way
| as to wash away some support or where heavy vehicles have
| cracked the road surface allowing water in which
| subsequently freezes. If the road is properly constructed
| and maintained with sufficiently good drainage on both
| sides frost heave (telehiv in Norwegian) should not be a
| problem.
| freeone3000 wrote:
| It might honestly be easier to fix freeze-thawed cracked
| pavers than having to rip up asphalt and lay it back down.
| dublinben wrote:
| Every residential street should be paved with bricks or other
| paving stones, instead of asphalt. It's safer, because people
| drive more slowly. The maintenance costs are also lower.
| quesera wrote:
| Bricks and pavers are very difficult to plow safely. They
| are also more expensive than asphalt.
|
| But for warm, affluent locations, they make sense.
| CalRobert wrote:
| But bumpy is good!!!! A bumpy street is one where you drive
| slowly and don't run over children riding bikes to school. A
| bumpy street is one where you pay attention. A bumpy street
| says "you may drive here but this is not a space _just_ for
| your car".
|
| If only they were more common outside the Netherlands. I love
| my bumpy, brick, tree-lined, narrow, street.
| NikkiA wrote:
| TBF, my experience of america when I lived there, was that
| black asphalt was far less common than light grey (and thus
| higher albedo) concrete for both. Increasing albedo is
| considered to be one of the geo-engineering solutions to try.
| inglor_cz wrote:
| I live in a place where we have a Tesco mall with a big parking
| lot nearby, but then I have to walk a path through a green area
| with mostly grass, but some trees and bushes as well.
|
| The temperature difference is staggering. In hot summer, the
| parking lot is unbearable and the green area feels much better.
| In early spring/late autumn, the parking lot is uhm-okay
| (though still ugly), while walking through the green area gives
| you shivers: cool and wet wind.
|
| Only in deep winter, during the freezing days, both areas feel
| the same.
| Mizza wrote:
| I've become really obsessed with 'Miyawaki Forests' lately -
| small, dense, urban forests which can reach a mature state in
| only a few years. I hope they start showing up everywhere. Fuck
| minimum parking requirements, where are the minimum forest
| requirements?
| FredPret wrote:
| Incredible - apparently you can do one in your back yard!
|
| https://canadiangeographic.ca/articles/the-many-benefits-of-...
| crazygringo wrote:
| I'm having a hard time picturing what they look like -- and
| the photo in that article is unrelated.
|
| Googling them, I can find images of a few proof-of-concept
| plots in the middle of fields but I can't find a single
| example of how they might integrate with a city.
|
| It would be nice to see some kind of before-and-after, even
| if just an illustration, to get a sense of how they would fit
| into a cityscape aesthetically and practically.
| burkaman wrote:
| Here's a NYT article with some good photos, gift link:
| https://www.nytimes.com/2023/08/24/climate/tiny-forests-
| clim...
|
| Here's a photo of what it looks like when it's first
| planted: https://voice.somervillema.gov/miyawaki-micro-
| forest
| 3D30497420 wrote:
| Another good article:
| https://www.creatingtomorrowsforests.co.uk/blog/the-
| miyawaki...
| Luc wrote:
| PDF with lots of pictures and information: https://urban-
| forests.com/wp-content/uploads/2020/05/Report-...
| JadeNB wrote:
| They're surely extremely region-specific--sourcing with
| native trees is a big part of their sustainability. Do you
| know anything about where to find local growing guides for
| different regions?
| burkaman wrote:
| Here's one site that seems solid:
| https://nativeplantfinder.nwf.org/
|
| Note though that your climate is changing, and what was
| historically considered native for your region may no
| longer be a good fit: https://heatmap.news/is-native-
| gardening-becoming-pointless
| Aromasin wrote:
| I'd love to know if there was an equivalent one for species
| native to the UK.
|
| EDIT: Found a great list after a little investigation!
| https://www.north-norfolk.gov.uk/tasks/projects/miyawaki-
| for...
| sp332 wrote:
| It doesn't always have to be trees. Hedgerows can be good
| too.
| ajb wrote:
| And a good thing too, because trees in London cause havoc
| with all the Victorian houses with no foundation in the
| modern sense.
| pvaldes wrote:
| That 3x3m project shown is not realistic. Not for a newbie
| and probably not easy to keep from falling apart for an
| expert.
|
| But yes, wild hedgewoods of a mix of useful shrubs are
| totally doable even in really small spaces. I had designed a
| few. They are low maintenance, beautiful, useful, funny, and
| tasty and everybody should have space for one of this
| wildlife lifesavers in their gardens.
| jay_kyburz wrote:
| I bought three boxes of Microforest from Edwina Robinson here
| in ACT Australia and planted them in my front yard.
|
| Here is an article about her project.
|
| https://www.abc.net.au/news/2021-07-08/act-micro-forests-
| in-...
|
| It's been two years, the some of the trees are well over 2m
| tall already.
| mobilemidget wrote:
| Accidentally I recently looked up when a bunch of trees are, or
| can be called a forest. Which I learned is minimal 500 square
| meters.
| thfuran wrote:
| How many trees have to be in that region?
| quixoticelixer- wrote:
| There isn't actually a strict definition of what is or isn't
| a forest
| jimkleiber wrote:
| From minimum parking requirements to minimum park requirements
| :-)
|
| Ok maybe minimum forest requirements is more accurate but had
| to do it
| darth_avocado wrote:
| The idea that everything needs to be a dense forest is a
| problem. What is more helpful is a variety of ecosystems
| available. I don't have a lot of space, but I managed to have 4
| ecosystems in all of my yards with 200+ species of plants:
| California chaparral, Coastal forest, Xeriscape and a
| wildflower meadow. Cities could also build such environments
| and that would be more positive than just planting Miyawaki
| Forests everywhere.
| binonsense wrote:
| I can't imagine these forests will pop up "everywhere". Seems
| like a groundless concern.
| Affric wrote:
| > I hope they start showing up everywhere.
|
| For people in urban hellscapes? Yes.
|
| For non-human animals? More complicated. These sorts for
| forests are generally dominated by "edge species". Edge species
| generally do relatively well out of habitat fragmentation.
|
| The most sensitive species that need a lot of depth in forest
| generally don't do well with these small pockets.
|
| This is not to say that Miyawaki forests aren't an improvement,
| just that their "conservation" value is limited and still need
| to preserve/manage huge amounts of actual contiguous forest
| with a minimum perimeter compared to the area covered.
| TulliusCicero wrote:
| That's fair. It's definitely a complementary thing, you want
| both types of forest I'm sure. Small forests don't cover all
| the needs, and large forests don't fit everywhere.
| pkphilip wrote:
| I have always been very curious as to why many cities do not push
| for more forests to cool down the place. I studied in a college
| with a lot of trees on campus and the temperature was at least 5
| C cooler than just outside the college.
| nxm wrote:
| Because more housing is seen as a more immediate and higher
| need
| FirmwareBurner wrote:
| Because parking spaces or other such things are more profitable
| for business owners and the city.
|
| Nobody can monetarily profit from trees, unless you were to
| charge people money for time spent under their shade.
| bongodongobob wrote:
| You act is if the people living there don't want parking
| spaces.
| c0nfused wrote:
| As city dweller, I really would like less parking in my
| city.
|
| Turns out surface parking is a better $/sqft than garages
| once you count maintenance. This means that the core part
| of the city where density is greatest is ringed by a 2-5
| block wide wasteland of surface lots. Its not great.
| Especially now that work from home is a thing and the
| divide between people who live here and people who drive
| here to work is obvious because the suburb people aren't
| here any more but their parking spaces still are
| mjevans wrote:
| The parking spaces are still there because the city's
| 'density' or 'daytime population' was pumped by
| ecologically unsustainable commutes.
|
| The US has never had a high level civic planning process
| or ability. Housing ends up built where-ever, and it's
| often cheapest to go built it in places with less
| regulation. Like wild frontiers in not even states. Or in
| areas outside of city limits as a tax dodge. There also
| aren't formal processes for renewing areas; instead
| informally they're allowed to decay and crime rise, and
| eventually reach a point where it becomes 'economically
| viable' for building something new.
|
| Those lots exist because there's still enough whatever is
| desired in the city you live in, probably too much retail
| and office space. Probably not enough apartment / condo /
| housing space, but none of those investors want to admit
| their market was over-valued and de-value the present
| investments so they'll happily keep supply low and rents
| high.
| acdha wrote:
| Parking spaces by definition benefit people who drive,
| which usually means someone well out of walking distance.
| That leads to some interesting dynamics where people who
| are enough richer to have nice separated homes use their
| social status to demand parking everywhere even though the
| main thing people near those spaces get out of it is
| negative health impacts.
|
| One interesting angle involves small businesses: you'll
| often see owners interviewed complaining about losing
| parking spaces. This makes no sense for a local business,
| and there are decades of studies showing that
| pedestrian/transit/bike traffic generates more revenue for
| small businesses (if you're already in the car, you're
| probably continuing to a big store) but it makes total
| sense when you realize that the owners are far more likely
| to live out in the suburbs and are making the mistake of
| assuming this is also true of their customers. There's a
| staple in some city planning debates of noting that the
| people complaining loudest about how their customers won't
| stop if they can't park right in front are often leaving
| their own cars in those spaces all day.
| devilbunny wrote:
| > pedestrian/transit/bike traffic generates more revenue
| for small businesses
|
| Sure, if you have a walkable/transitable/bikeable city.
| If you _don 't_, then losing parking spaces can be an
| issue.
|
| I would have to walk for 24 Google Maps minutes to get to
| the nearest store of any kind. And I'm close; people
| farther down the main road that feeds my street could
| face almost an hour's walk each way (with no sidewalks or
| shoulders; you're walking in a ditch) to get to the same
| place. Several large hills along that route and a hot,
| muggy climate means that nobody is going to bike it.
|
| My niece, from Colorado, came to visit her grandfather
| (my dad). She wanted to go for a hike in the South in
| July. I said sure, I'll take you. Five minutes into it,
| she said, "Now I know why everyone is fat here. This is
| miserable." And my reply was "Yes, and this isn't as hot
| or as humid as it gets. It's actually not that bad
| today."
| acdha wrote:
| We're talking in the context of cities so I was only
| referring to more dense scenarios. I agree that rural or
| really low-density suburban communities are different.
|
| The key point is really just the function of distance:
| people who live near a small shop will go there due to
| convenience. If it's far enough to need a car, they'll
| probably keep going to a bigger shop with lower prices
| because the cost of having and using the car is already
| incurred and the cost of doing anything else is greater.
| NewJazz wrote:
| Street parking in a lot of cities in america is notoriously
| "free". I think somebody wrote an article about how in SF,
| their car pays less rent per sqft than they do.
| kapp_in_life wrote:
| >their car pays less rent per sqft than they do
|
| This shouldn't be surprising though. Cars don't need
| heating or cooling or sewage or a roof or ...
| yifanl wrote:
| People who live there profit from the trees through quality
| of life benefits (such as being 5 degrees cooler). Maybe part
| of the problem is that a lot of landowners tend to not live
| in the land they own, so they can't see these profits.
| FirmwareBurner wrote:
| I was talking about monetary profit not quality of life
| profit.
| yifanl wrote:
| Money is just an abstraction for quality of life :)
| nonrandomstring wrote:
| In Britain I've seen trees planted in urban spaces. And then
| local residents come and pour rock-salt and weed-killer on
| the saplings there - because it stops them parking.
| graemep wrote:
| On the other hand in Sheffield there was a huge movement
| from residents to stop the cutting down of trees. Everyone
| I know there supported it.
| is_true wrote:
| Add a tax for those that don't have trees. There you have
| your incentive. It's so easy, unfortunately taxes aren't
| often used this way.
| BurningFrog wrote:
| The whole point of a city is to concentrate human activity in a
| small area.
| acdha wrote:
| That doesn't mean you can't have trees: a high-rise building
| next to a park is quite dense, as are tree-lined streets.
|
| The problem is those streets: the 20th century model focused
| on maximizing individual vehicle usage, which meant lots of
| open space for safe operation and subsidized storage. Cars
| can't go around trees like pedestrians or bicyclists and
| owners don't want branches falling on their parked cars, so
| anywhere there isn't enough space for both it tended to
| result in more heat-amplifying asphalt.
| kjkjadksj wrote:
| Most land that isn't already a park is privately owned. Most
| cities can't afford to buy out a forests worth of real estate
| let alone clear it and replant it.
| BurningFrog wrote:
| Reading past the headline, the effect is from trees providing
| shadow, and evaporating water cooling the air.
|
| You don't need any actual botanical gardens.
| tonmoy wrote:
| But it's probably the easiest and cheapest way. Another plus
| point would be creating habitat for smaller animals and morale
| boost for the city inhabitants
| Cthulhu_ wrote:
| Well, both require making land available, and while amenity
| gardening is manageable, a botanical garden is often a
| research site that requires a lot of expertise to set up and
| maintain. Mind you, that's just fine, the county can and
| should hire people.
| Filligree wrote:
| > botanical garden is often a research site that requires a
| lot of expertise to set up and maintain
|
| But it doesn't have to be, right? It's just that we don't
| have very many, so the ones that do exist end up being
| research sites.
| BurningFrog wrote:
| Looking out my window, I see trees planted on the sidewalk
| along a road.
|
| It takes little space away from pedestrians, but provides a
| lot of shade. That seems both easier, cheaper and better that
| taking up whole city blocks.
| GrumpyNl wrote:
| We need more trees, i am shouting that for years.
| andsoitis wrote:
| If your city cannot afford botanical gardens, then planting trees
| on sidewalks, more boulevards, and other places not only bestow
| _ecological benefits_ but is also good for the human psyche and
| _reduces crime_.
|
| https://www.fs.usda.gov/research/treesearch/40701
| sokoloff wrote:
| Does _planting trees_ reduce crime?
|
| Or are areas that have planted trees areas that also tend to
| have reduced crime?
|
| The abstract of that paper indicates an inverse _correlation_
| between trees and crime, but stops well short of claiming or
| proving a causal relationship.
| kwhitefoot wrote:
| > Or are areas that have planted trees areas that also tend
| to have reduced crime?
|
| Perhaps fake it till you make it?
|
| Worth a try surely.
| B56b wrote:
| The correlation they saw was after controlling for
| potentially confounding variables, like income level, housing
| stock, density, and demographics, as explained in this
| article: https://caseytrees.org/2023/09/mythbusting-trees-
| and-crime/.
|
| So of course it's not proof of causation, but reverse
| causation(nice neighborhoods lead to more trees planted)
| seems unlikely to explain the effect.
| crazygringo wrote:
| This feels misleading.
|
| I totally believe that botanical gardens cool the air _within_
| them. That 's what happens when you have an area full of trees
| and shade, with denser vegetation than a park.
|
| But I have a hard time believing that they have any significant
| effect on the city air 5 or 10 blocks away, where the asphalt is
| baking in the sun.
|
| So I'm not sure what the point of this article is, because it's
| not like we're going to replace half the blocks in a city with
| botanical gardens, as nice as that would be.
|
| Meanwhile, the article claims claims planting trees on the street
| has _less_ effect, but surely is far _more_ important -- because
| it affects the whole city, rather than a small localized area in
| and around a botanic garden?
|
| So there seems to be a major flaw in this article, in that it's
| comparing the cooling effects of various interventions (botanical
| gardens, street trees, etc.) but without ever specifying how the
| sizes or densities are being compared.
|
| Honestly, I can't even imagine what a unit of comparison between
| botanical gardens and street trees would be, since botanical
| gardens _replace_ streets and buildings, while street trees
| merely _add_ to them. It 's apples and oranges.
| mariusor wrote:
| I don't see anywhere in TFA where it's implied that the
| temperature drops as an average, or that somehow it extends
| past the green area. I feel like you've been misled by a
| strawman that you created yourself.
| nottorp wrote:
| Empirically, it extends a tiny bit past the green area.
|
| When I go for walks in summer in my city, it's noticeable how
| the temperature drops _while on the sidewalk_ when I walk
| past a green area as opposed to past a building.
| cnity wrote:
| Thermodynamically it must. High temperature will flow
| towards low temperature areas like a heat-sink, where it is
| cooled by the shade and vapour.
| ako wrote:
| It's actually the opposite. High temperature air rises
| (by expanding and becoming less dense), the void is
| filled with low temperature air. So a colder forest will
| start a wind outward of the forest towards the warmer
| areas, thereby distributing the colder air into the
| surrounding area.
| timeon wrote:
| > But I have a hard time believing that
|
| Have you built your argument against the study on belief?
| zdragnar wrote:
| I think the article addresses this fairly well. In addition to
| shade, evaporation from open water and plant leaves
| contributes, as does the soil acting as a heat sink.
|
| Botanical gardens are only slightly more effective than trees
| over roadways from their study, so shade is likely the
| strongest factor, but the others clearly play a part- from
| cooling down enough overnight compared to roadways and cement
| to the evaporation from the denser vegetation having a stronger
| effect.
|
| The thing that I missed was how such a garden compared to an
| open, grass park. The difference in vegetation density would be
| clearer, I think, and might better explain the difference
| measured between trees over roads and gardens.
| athenot wrote:
| From an energy perspective it makes sense, since at least
| some of the solar energy hitting tree leaves is used for
| photosynthesis, and reducing Carbon out of its oxydized
| state. So it's not just accumulated/reflected like for
| pavement.
| mlyle wrote:
| Effectively none of the incident energy is used for
| photosynthesis.
|
| Much bigger effects are reflecting energy well above things
| that can store heat, and acting as evaporative coolers.
| onlyrealcuzzo wrote:
| Interesting how easy it is to mitigate 5C - and yet we think
| the world is going to end if temps increase another 2C - when
| we are basically in an Ice Age and the Earth has only been
| cooler for brief periods of time in the last 500M years:
| https://www.climate.gov/news-features/climate-qa/whats-
| hotte...
|
| Luckily, fossil fuels are going to get phazed out massively
| over the next 50 years strictly due to economics.
| emj wrote:
| You are mistaking global for local, and 50 years is too
| late. I am positive I think some of us will survive.
| Jabbles wrote:
| Did you read the link you posted? Specifically the update
| at the top?
| Aloisius wrote:
| Easy to mitigate it in _urban_ environments which are heat
| islands due to the low albedo of man-made surfaces. 99% of
| the earth, however, is not paved.
|
| Reducing heat on a _global_ scale is a wee bit more
| difficult.
| macromagnon wrote:
| The increase in temperature is just one of the issues. It
| has probably been mainly publicized as it's an easy "key
| performance indicator" to get the point across/that can be
| succinctly referred to. Sea level rise, ocean
| acidification, global weather pattern shifts, etc. are all
| also major problems.
| cnity wrote:
| They do have a significant effect. Trees scoop up rain from the
| soil, lift it through their trunks and up into the leaves where
| little mouths (stomata) in the leaves deposit that water back
| into the air in a process called transpiration.
|
| It is actually in this way that places deep inland can still
| receive rainfall. Without this process clouds wouldn't be able
| to make it far inland.
| kevstev wrote:
| Complete anecdote here, but I live on a park that is about two
| acres big. Its filled with large old (~100 years) trees and
| lawns, though it does also cram in a basketball court and two
| tennis courts. In the summer heat, when we walk around our
| area, the temperature astonishingly drops about 5 degrees once
| you get within 2-3 blocks of the park. Its striking in how
| noticeable it is. I have no idea why, but it seems even a bit
| of green space can have a big impact.
| ako wrote:
| High temperature air rises (by expanding and becoming less
| dense), the void is filled with low temperature air. So a
| colder forest will start a wind outward of the forest towards
| the warmer areas, thereby distributing the colder air into the
| surrounding area.
|
| You can see the same effect mostly in spring in coastal areas,
| when the land is heated faster than the sea. Hot air over land
| will rise, colder air from the sea will move in, causing
| thermal wind, making the coast a lot cooler. This can cause
| enough wind for kitesurfing or wingfoiling.
| Anotheroneagain wrote:
| I think it's misleading for a worse reason: These trade
| temperature for humidity. They seem to work great as long as
| the temperatures don't go too high. They become hot ovens when
| they would be the most needed.
| ddalex wrote:
| I wonder if they could cool down a desert; let's say, make
| nuclear reactors and plant them on the edge of Sahara, and do one
| thing with them: desalinate water from the sea; use the water to
| irrigate large portions of the desert, and plant them with
| bamboo; this will cool the desert, sequester CO2, and have global
| influence on the climate warming.
|
| Back on the envelope calculations: 3.5 kWh/m^3 to desalinate
| water, 10 nuclear reactors, 1sq meter for a bamboo plant, you can
| water and grow 5.5 billion bamboo plant; let's say each plant
| fixes 10kg of CO2 per year, you reduce 10% of world's emissions
| in one clean sweep, for a total investment of maybe 100 billion
| USD
| jamie_ca wrote:
| Desalination doesn't produce (freshwater + salt), it produces
| (freshwater + saltier water). Dealing with the waste brine is a
| challenge if you want to process that much in such a localized
| area.
| marcosdumay wrote:
| The area is very clearly not "localized".
| quesera wrote:
| The real problem is that the cost would be outrageous.
|
| If you go this route for greening the Sahara, you could allot
| 5% for the evaporation ponds to turn brine into dry salt.
|
| There are other reasons it will never happen, but this one is
| solvable! :)
| xbmcuser wrote:
| you can't do mass change like that. This will change weather
| patterns could result in a lot of rain being sucked into the
| Sahara and make South America a desert.
| https://news.mongabay.com/2015/03/how-the-sahara-keeps-the-a...
| com2kid wrote:
| Human activity has lead to the Sahara being much larger now
| than it was in the past. There are ongoing efforts
| (https://www.youtube.com/watch?v=WCli0gyNwL0) to try and keep
| the Sahara from growing any more.
| araes wrote:
| There have been a couple attempts to do this previously. In
| India, there was one version used as a physical barrier on a
| customs line for 450 miles. Also happened to improve the area.
|
| https://en.wikipedia.org/wiki/Inland_Customs_Line#Great_Hedg...
|
| https://amocarroll.com/projects/tracing-the-great-salt-hedge
|
| China has the China's Three-North Shelterbelt Program where
| they're trying to hold back the desert in North China and Inner
| Mongollia.
|
| https://en.wikipedia.org/w/index.php?title=Three-North_Shelt...
|
| Based on reports, it has issues with tree survival, yet seems
| to be making progress based on aerial surveys.
|
| https://www.sciencedirect.com/science/article/pii/S259033221...
|
| There's also an attempt in Africa in the Sahara that a bunch of
| countries signed on to. Unfortunately, their commitments have
| mostly amounted to talk without much funding or governmental
| support. Seen a few videos of locals who seems to believe in
| the idea, its just not getting much large scale help.
|
| https://en.wikipedia.org/wiki/Great_Green_Wall_(Africa)
|
| I also use Ecosia (https://www.ecosia.org/) as a web browser,
| and they supposedly plant trees based on number of searches and
| a percent diversion of search revenue. Seems to at least have
| some photographic evidence of money actually being spent
| somewhere.
|
| Senegal's an example with desert work. Seems to have evidence
| that at least some amount of trees are being planted with
| videos (harder to falsify).
|
| https://blog.ecosia.org/senegal/
|
| https://blog.ecosia.org/tag/senegal/
| BurningFrog wrote:
| Saudi Arabia is building a mega-project that's kinda like that:
|
| https://www.youtube.com/watch?v=-13bKIS75Gk&ab_channel=TheIm...
| downrightmike wrote:
| You need a ton of water just to run the reactors and the
| droughts have already required ones that are in desert like the
| Palo Verde plant to reduce output.
| karaterobot wrote:
| The chart and table in that article are confusing. They seem to
| indicate that if a city has botanical gardens, wetlands, green
| walls, street trees, balconies, permeable paving, woodlands,
| playgrounds, adopted public spaces, and mixed biomes, the air
| temperature would be reduced by 35degC. If so, I'm prepared to
| ban all these things to prevent our cities from becoming frozen
| hellscapes.
| walthamstow wrote:
| I'm not sure. I live in London, 51 degrees north. We have a lot
| of parks in London, but the bus stops near them still have deep
| grooves of melted asphalt from recent heatwaves.
| n4r9 wrote:
| Perhaps it would be even worse without the parks? This article
| suggests that variation in temperature across the city does
| correlate with vegetation cover:
|
| > the Kilburn and South Hampstead area, with 38% vegetation
| cover, experienced heat over 7degC hotter than Regent's Park,
| with 89% vegetation cover, a short distance away.
|
| https://www.pbctoday.co.uk/news/digital-construction-news/bi...
| Kon-Peki wrote:
| I used to live in Chicago, and they managed this by putting a
| concrete pad at the bus stops that were high-frequency enough
| to get the grooves. The concrete pads are not bus-sized! They
| are only placed where the bus wheels are when the bus comes to
| a stop, with a little bit of a buffer since the bus doesn't
| stop in _exactly_ the same place every time.
| RecycledEle wrote:
| I wonder if the centers of cities are hotter now that they are
| all pavement and buildings than they were when they were
| grasslands or forests?
|
| Could this contribute to warming?
|
| Could warmer cities even cause us to overestimate the current
| temperature because the temperature 100 years ago on a prairie
| was less than the temperature today in a parking lot?
| bluGill wrote:
| Do you want to account for the people living denser in those
| cities and thus freeing up room in more rural areas?
| gatane wrote:
| Another reason to do guerrilla gardening, or seed bombs:
|
| https://en.m.wikipedia.org/wiki/Seed_ball#Seed_bombing
| bane wrote:
| I hope that the renewed interest in urban gardens and the
| appreciation for plant life in urban landscapes persists. The
| benefits can be wild in terms of improved quality of life for
| those living in the city.
|
| I live very near an urban core that is undergoing rapid
| development and densification. That core is part of a larger
| planned area that includes apartments, condos, town houses, and
| suburban style homes going back more than 50 years. The nearby
| suburban areas are walkable, and almost entirely embedded in so
| much greenery it's virtually a wildlife preserve. A local
| association owns some significant percentage of the land and has
| strict rules about development on their property which keeps it
| out of the hands of developers and well forested.
|
| My understanding was that all of these thousands of acres were
| virtually tree free farmland when it was selected for
| development. Now the entire area is absolutely filled with 30-70
| foot (10-20 meter or so) trees planted when development started,
| dense undergrowth, and absolutely chock full of various kinds of
| wildlife like deer, foxes, raptors, and so on. Yards are allowed,
| but not really required, so many people have just let them go
| fallow and return to nature, or keep minimal outdoor areas for
| lawn furniture or play areas for their kids.
|
| The urban area needs a place for rainwater runoff to go, so the
| runoff areas dump into artificial streams which have been
| designated as parks, and provided with paved trails, and bridges
| and so on. They too have become heavily forested, the only sign
| that they're part of the local urban infrastructure is the
| occasional manhole cover. The runoff condenses into a selection
| of local artificial lakes that open up opportunities for
| waterfront property and parks, and personal watercraft and
| recreation areas.
|
| I live in a suburban home, 3 miles from the middle of the urban
| core which features an Apple store and other big named retailers,
| as well as offices, restaurants, recreation etc. It's a nice walk
| on weekends or evenings. The core is connected into the nearby
| major city and other nearby urban areas and the local airport via
| light rail.
|
| In the summer, we're about 5-10 deg F cooler than all of the
| surrounding areas, and much more humid in general. Because of the
| trees, we get very little wind. It can sometimes be difficult to
| predict how to dress when going out as our house sits even cooler
| than that, and stepping outside is still not representative of
| the way it feels in other nearby areas. It can be _cold_ in our
| home in the early fall and late spring when the outside sits at
| around 20 deg C or 70 deg F.
|
| In some parts of the world this may sound absolutely normal, but
| here in the U.S. it's absolutely bonkers that it exists. My
| understanding was that it was explicitly patterned on a "more
| European" style of land development.
| inglor_cz wrote:
| Anecdotally, Spanish cities seem to have really beautiful and
| well-kept gardens.
|
| Might have something to do with mitigating the hot climate.
| (Cordoba during the summer is a veritable oven.)
| Ekaros wrote:
| Hmm, what is the general availability of water resources these
| would need in areas that would benefit most of them? If there is
| already droughts I don't think too much water usage could be
| afforded adding more vegetation.
| bluGill wrote:
| If you are planting native trees there should be no problem -
| there have been droughts before and so the trees can handle
| them. You might need to water them for the first 5 years, but
| after that they should be okay.
|
| Select trees that are not native (or native species but from a
| very different location) and you can run into problems.
| vondur wrote:
| I think this should be common knowledge that planting trees and
| having native green spaces in cities helps keep things cooler. In
| my neighborhood in Los Angeles, we have people who don't want
| trees in their yards and one who actually damaged a city planted
| tree in order to get rid of it. To a certain extent I get it,
| trees have to be maintained, which does cost money. We have a
| large and fast growing pepper tree in our yard, which is just
| over the line where the city would maintain it. We usually spend
| $700/year to have it trimmed back from hitting the house. I
| really appreciate how much shading it provides in the late
| afternoon in the summer.
| dunk010 wrote:
| Except plants increase the humidity, exasperating conditions.
| p0w3n3d wrote:
| Any grass can cool the city 5degC but city need to maintain it
| and first of all, need to sacrifice the money the city would make
| off of building another four flats on it
| zahma wrote:
| I hope this isn't a revelation to anyone at this point. Of course
| greenery reduces heat, but more than anything it means removing
| concrete, which mitigates the urban heat island effect. (Urban
| heat islands absorb heat energy during the day, amplifying
| extremes, and release heat at night, making it impossible for
| effective cooling.) And yet there is still so much resistance or
| otherwise apathy to the idea of planting more trees and removing
| space for vehicles -- as if it's merely some hippy-dippy shit
| only good for gentrification.
| vetinari wrote:
| Planting more trees and removing space for vehicles are two
| different things; it is not necessary to make them dependent.
| Those who do, usually do it for their anti-vehicle agenda, and
| planting green is only an excuse / a tool, not the objective or
| intent to improve the environment.
|
| If you want more space for parks and green, you can do it also
| other way. For example, like Hausmann did in Paris.
| zahma wrote:
| In a hierarchy of urban planning, I'd favor removing space
| for cars over demolishing precious space for affordable
| housing. To that effect, I wouldn't point to Haussmann who
| bulldozed plenty of homes and neighborhoods for his unified
| vision of Paris connected by major thoroughfares. As a
| result, we have few parks and the city lacks any kind of real
| arboreal shelter except on some of the boulevards. He was a
| visionary, but he didn't have scientific papers or the threat
| of climate change to contend with.
|
| The idea I have in mind is that the control over cities has
| been wrested from its citizens. A special car commuting class
| has more comfort moving about a city like Paris than regular
| inhabitants -- but at what cost and borne by whom? Removing
| space for cars means removing vehicles, which re-empowers
| city-dwellers, cleans the air, and cools the city.
| woodruffw wrote:
| In much of the US, the two are interdependent: to plant more
| trees on streets, for example, many US cities will need to
| trim the arterial roads that swallowed up neighborhood
| sidewalks half a century ago.
| LispSporks22 wrote:
| I didn't notice it until I got a motorcycle and started riding,
| because there's very little between you and the environment and
| you're moving so fast you can definitely feel the cooler and
| hotter parts of a city.
|
| Areas with trees, not necessarily sharing the road definitely
| feel a few degrees cooler
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