From USC and the evapotranspiration cools locally department:
Hidden, local climate impacts of drought-friendly vegetation
New research by USC Viterbi researchers explores the climate impact of drought vegetation efforts
To address the recent drought in California, policymakers have created incentives for homeowners to replace existing lawns with drought tolerant vegetation. However, new research from George Ban-Weiss, an assistant professor in the Astani Department of Civil and Environmental Engineering at the USC Viterbi School of Engineering, has found that these efforts might have some hidden consequences on local climate.
Ban-Weiss and post-doctoral scholar Pouya Vahmani used a model of the Los Angeles basin to investigate the climate impacts of widespread adoption of drought tolerant vegetation. Their findings, put forth in the article “Climatic Consequences of Adopting Drought Tolerant Vegetation over Los Angeles as a Response to the California Drought” in the journal Geophysical Research Letters, indicate that in fact, if all lawns were replaced with drought tolerant vegetation, that Angelenos could expect an average daytime warming of 1.3 degrees Fahrenheit due largely to decreased evaporative cooling, as irrigation is stopped. For the hottest regions of the Los Angeles basin, such as the inland empire and San Fernando valley, the researchers predict a daytime increase in temperature of 3.4 degrees Fahrenheit. Such temperature increases could exacerbate heatwaves, increase photochemical smog production, and increase air conditioning energy use.
However, one effect of widespread planting of drought tolerant vegetation– which the researchers believe could counteract these higher daytime temperatures– is an even greater decrease in nighttime temperatures. The researchers forecast that the average nighttime temperature decrease could be as much as 6 degrees Fahrenheit. Lower nighttime temperatures are important for preventing adverse human health consequences like heat stroke or even death during heat waves, says Ban-Weiss. People, especially vulnerable populations like the elderly, need temperatures to reduce sufficiently at night to allow their bodies to recover from high daytime temperatures and prevent heat-related illness.
“Our interest in this topic was initially piqued because we hypothesized that the reductions in irrigation associated with adopting drought-tolerant vegetation would cause temperature increases,” says Ban-Weiss. “We were surprised to find the reduced temperature signal at nighttime. But this actually has a simple physical explanation, since reducing soil moisture decreases upward heat fluxes from the sub-surface to the surface at night, subsequently reducing surface temperatures.”
“Our research highlights how water and climate are intimately coupled,” says Ban-Weiss. “You can’t change one without effecting the other.”
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Astroturf.
as someone who lives in a humid environment, I’d rather the solar energy go into sensible heat rather than latent heat. I hate humidity.
You would not have liked my boyhood hometown of Galveston, Texas much then, even though it rarely hit 90F in the summer.
Or even better sensible electricity which can be used to run and air-con 😉
Dr. Spencer, I’ve lived my whole life in SE Georgia. I hate the heat and humidity. I once read a biography of George Whitefield, missionary to the colony of Georgia in the 1700s. I remember his description of summers in GA. He said that all a man could do during the day was lie on the dirt floor, otherwise he would die.
I suggest solar panels everywhere. It’s shady underneath and you are doing the Creator’s work.
In the UK some years ago we were told we would need to grow drought-resistant plants and, shortly before the deluges began, one well-known gardener here turned a car park into such a garden. Don’t hear so much about that now…..
I miss driving through LA when the jacarandas are in bloom.
http://farm4.staticflickr.com/3160/2967327065_c84714fa9a_o.jpg
“Drought tolerant landscaping” sounds less mean than that the nitrous oxide emitted by lawns is a ghg.
https://wattsupwiththat.com/2010/01/19/save-the-planet-from-ghgs-use-astroturf/
“Turfgrass lawns help remove carbon dioxide from the atmosphere through photosynthesis and store it as organic carbon in soil, making them important “carbon sinks.” However, greenhouse gas emissions from fertilizer production, mowing, leaf blowing and other lawn management practices are four times greater than the amount of carbon stored by ornamental grass in parks, a UC Irvine study shows. These emissions include nitrous oxide released from soil after fertilization. Nitrous oxide is a greenhouse gas that’s 300 times more powerful than carbon dioxide, the Earth’s most problematic climate warmer.
“Lawns look great – they’re nice and green and healthy, and they’re photosynthesizing a lot of organic carbon. But the carbon-storing benefits of lawns are counteracted by fuel consumption,” said Amy Townsend-Small, Earth system science postdoctoral researcher and lead author of the study, forthcoming in the journal Geophysical Research Letters.”
More babbling vomit to justify destroying the only CO2 sequestration that is known to actually work, by using gross estimates, which like models, produces the results Greenie fools want.
Believe me, the Californians have been doing this for a couple of centuries and have some of the most beautiful plants and trees, which grow almost totally effortlessly, in every yard in the LA basin.
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There are pomegranates and bougainvilleas, jacarandas, citrus, and anyone there can stick a rose branch in the ground and it will take root. They are very fond of small evergreen hedges with agapanthus. For ground covers, the ice flower plant can grow next to freeways in the highest temps (it’s a succulent):
http://cf.ltkcdn.net/garden/images/std/182046-425×319-ice-plant-groundcover.jpg
and with a little shade, the baby’s tears in LA make an easy filler between stones.
http://i.ebayimg.com/images/g/gSIAAOSwstxU5XiP/s-l400.jpg
I wouldn’t let the environmentalists in the government plant your property from their dried up, prickly little approved list. Don’t be too polite to tell them it looks nasty.
Greg, all rocks are biodegradable. The harder ones take longer for water and gravity to do their thing.
Believe me, the Californians have been doing this for a couple of centuries and have some of the most beautiful plants and trees, which grow almost totally effortlessly, in every yard in the LA basin.
There are pomegranates and bougainvilleas, jacarandas, citrus, and anyone there can stick a rose branch in the ground and it will take root. They are very fond of small evergreen hedges with agapanthus. For ground covers, the ice flower plant can grow next to freeways in the highest temps (it’s a succulent):
and with a little shade, the baby’s tears in LA make an easy filler between stones.
I wouldn’t let the environmentalists in the government save you from choices in the finest growing zone in the country, and plant your property from their dried up, prickly little approved list. And don’t be too polite to tell them it looks nasty.
Curb appeal and personal garden rooms are a very large part of a home’s value.
[Moderators, can you put me back on the white list? I am not that other guy (: ]
Here in Southern California if gardens are not watered they will die back Most of what one sees in the suburbs and along the freeways is not natural. The truly natural vegetation in the LA basin has to be very drought tolerant to survive. For example the Ice Plant one sees growing in freeway landscaping is imported and requires substantial watering to keep it from dying back and disappearing altogether.
That rebound topic again:
However, one effect of widespread planting of drought tolerant vegetation– which the researchers believe could counteract these higher daytime temperatures– is an even greater decrease in nighttime temperatures.
Renewable resilient. tsomb’c.
Greater net cooling found…time to relocate the thermometers….
Just look at Dubai over the last 30 years. The more trees and grass they plant, the greener it gets and wetter. thus California needs to plant much more grass and trees. Dubai also ensures they have enough water for it as well now aided by wetter climate.
California has AB32 a carbon tax scheme to lower CO2 emissions. The flip side is CO2 sequestration. Along this second front, I got a letter to cut my water use 90%. So I water enough to keep the shrubs and let the lawn die. So did most of Californians. I have estimated my biomass dumping which is easy to do because we have separate containers in the state for lawn clipping trash. Based on my property size, extrapolated to the sizes of CA central valley and coastal major cities, the demand to destroy our landscaping I estimate just destroyed 20% of the state’s carbon sequestration. That is how CO2 policy works in California. From junk bond status to investment grade right after AB32 income started to roll in, then kill you lawns to keep 20% more CO2 in the atmosphere, because hey, who really cares. And so it goes. Welcome to a Democratic Party state.
In the meantime, Greenies are running around calling lawns evil. Okay they never heard of sequestration with plants, the only method that actually works. Also, they obviously don’t have carpenter ants. The only thing that keeps them out is grass. You cannot afford enough pesticide, and no, it doesn’t work anyway. Lawns keep down dust here, which in Lancaster, CA high desert, is fine loam. This is very readily airborne. And of course, it keeps the properties cooler, which should have an effect on airconditioning use. Bad, evil lawns. We need something high tech like more research on olivine for sequestration and then build billion dollar chemical plants to run them because having lawns in just so low tech, you know, passe.
Just put white sand in your lawn. It will reflect sunlight and cool the lawn and you don’t have to water the invisible plants
http://www.intoourelement.com/wp-content/uploads/galleries/post-2232/full/JKW_4468web%20White%20Sand%20Dunes.jpg
An article displaying the UHI effect was in the South Australian newspaper last week
http://www.adelaidenow.com.au/news/south-australia/heat-mapping-pinpoints-hot-spots-where-the-pavement-reaches-temperatures-of-up-to-70c/news-story/6999b98107fef516f7f4abb57c2dd12f
Notable comments from the link:
– the main Adelaide temperature gauge is at Kent Town, close to the city centre so surrounded by areas such as they show with a huge temperature range. Heavy ‘adjustments’ needed to get the ‘official’ temp.
Pretty obvious, I would have thought but not ‘official’ until someone gets a grant to study it
Here in Scotland we have a simple solution to the problem of garden lawns: we grow moss and call it a “lawn”.
Drought tolerant vegetation is the norm for pre human Southern California. Much of Southern California is semi arid to semi desert. Very green vegetation in winter turns brown and dry in Spring as the rains disappear. It is Mankind that has made Southern California a much wetter place then it would be naturally. Is trying to revert a place back to its natural state an environmental mistake?
As everyone in Florida knows, it’s not the heat, it’s the humidity!
Years ago I took out all the grass around my house and replaced it with cypress mulch. I added in a variety of natural Florida plants that, once established, do not need much water. Because they are native to Florida they can also handle times of heavy rains. So it should not be so much
“desert” plants but rather plants that are native to the area, plants that are adapted to the local climate of the area.
But they dont do that in Dubai and its flourishing, getting wetter and greener.
Here in the Texas Panhandle the ranchers know how to mitigate a drought. Polyculture forage will encourage deep roots and roots at various levels, improving the ability of the soil to retain moisture even during drought, and will provide a local ecology that will support more biodiversity, from primary plants to pollinators to insects to foraging small animals. It will also prevent overheating of the soil.
Some people / even landscapers who should know better, have a really flawed concept of drought tolerant. The lazy persons version is doing some crushed rock with a few low water plants (like the photo). That’s lame. Drought tolerant does not need to mean very little ground cover. There are all kinds of covers that are drought tolerant. So everything is still nice and green but not as thirsty as a blue grass lawn. There are even drought tolerant lawns.
So the standard is natural then?
I don’t think covering your property with row covers/landscape fabric–a petroleum product–is natural.
For a trifling investment of water, these plants perform many natural uses.
1. drainage
2. run off control
3. green spaces
4. wind breaks
5. generation of oxygen, fresh air in LA
6. shade and ornament
7. edible landscaping
8. places for kids to play outside
9. increased home value
Now it is true that lawns take some water but there are flash floods in the area and a good root system and established ground cover offers anatural solution, plus it’s prettier and more natural than cement for those purposes. Lawns only take up about 1% of the land so it is rather pathetic for the environmentalists to go hunting after a natural control for run off and a source of fresh air, and a natural source of enjoyment for all ages, in order to replace it with weedcover fabric and rocks.
Let’s take a look at government environmentalist landscaping in Tehachapi:
The first word that comes to mind is… not “natural”. The word that came to my mind I am not going to say.
Meanwhile, anyone who can grow a pomegranate (Iran, India) or a bougainvaillea (South America), and doesn’t, is not
natural!