Read the Beforeitsnews.com story here. Advertise at Before It's News here.
Profile image
By Desdemona Despair (Reporter)
Contributor profile | More stories
Story Views
Now:
Last hour:
Last 24 hours:
Total:

Will replacing thirsty lawns with drought-tolerant plants make L.A. hotter?

% of readers think this story is Fact. Add your two cents.



Desdemona Despair

By Deborah Netburn
2 August 2016

(Los Angeles Times) – Last summer, a revolution occurred in Los Angeles landscaping: Across the city, tens of thousands of homeowners tore up their water-thirsty lawns and replaced them with gravel, turf, decomposed granite and a wide range of drought-tolerant plants at a rate never seen before.

The water-saving benefits of this massive landscape overhaul are undisputed — and that’s important in a region that was facing what researchers called the worst drought in 1,200 years. Still, some experts warned that Angelenos’ zeal to use less water in the backyard would ultimately make the city warmer.

“Gardens and lawns act as air conditioning for L.A., which is only getting hotter with climate change,” landscape designers Mia Lehrer, Claire Latané and Margot Jacobs wrote in a 2015 op-ed in the Los Angeles Times. “Plants and trees provide shade and transpire moisture to cool the air; gravel and artificial turf don’t.”

The trio advocated replacing water-hungry landscapes with living landscapes that require almost no irrigation at all. But an environmentally sensitive Angeleno might still find herself confused: Could even savvy drought-tolerant landscaping cause the city to heat up? 

Now there is a scientific answer to that question. 

In a paper published Monday in Geophysical Research Letters, University of Southern California post-doctoral research associate Pouya Vahmani and USC civil and environmental engineering professor George Ban-Weiss analyze what would happen to the city’s overall temperature during the month of July if every lawn were replaced with drought-tolerant plants.

After running different land-cover scenarios through a climate model tailored to Los Angeles’ unique mix of coastal breezes, mountains and expansive urban cover, the authors report that a lawn-less Los Angeles would be up to 3.4 degrees warmer during the day than it is now. As expected, this warming would mostly be due to decreases in irrigation, the researchers said.

But there’s a flip side. The authors also report that transforming lawns to drought-tolerant vegetation has an average nighttime cooling effect of about 5.4 degrees that more than makes up for the daytime warming. 

“We hypothesized that our model would predict daytime warming, but we did not anticipate the nighttime cooling signal,” Ban-Weiss said. “In retrospect, it makes sense that reducing soil moisture would change the thermal properties of the soil and surface-atmosphere coupling in this way.” [more]

Will replacing thirsty lawns with drought-tolerant plants make L.A. hotter?


ABSTRACT: During 2012-2014, drought in California resulted in policies to reduce water consumption. One measure pursued was replacing lawns with landscapes that minimize water consumption, such as drought tolerant vegetation. If implemented at broad scale, this strategy would result in reductions in irrigation, and changes in land surface characteristics. In this study, we employ a modified regional climate model to assess the climatic consequences of adopting drought tolerant vegetation over the Los Angeles metropolitan area. Transforming lawns to drought tolerant vegetation resulted in daytime warming of up to 1.9 ° C, largely due to decreases in irrigation that shifted surface energy partitioning toward higher sensible and lower latent heat flux. During nighttime, however, adopting drought tolerant vegetation caused mean cooling of about 3 ° C, due to changes in soil thermodynamic properties and heat exchange dynamics between the surface and ground. Our results show that nocturnal cooling effects, which are larger in magnitude and of great importance for public health during heat events, could counterbalance the daytime warming attributed to the studied water conservation strategy. A more aggressive implementation, assuming all urban vegetation was replaced with drought tolerant vegetation, resulted in an average daytime cooling of 0.2 °C, largely due to weakened sea-breeze patterns, highlighting the important role of land surface roughness in this coastal megacity.

Climatic consequences of adopting drought tolerant vegetation over Los Angeles as a response to California drought



Source: http://www.desdemonadespair.net/2016/08/will-replacing-thirsty-lawns-with.html


Before It’s News® is a community of individuals who report on what’s going on around them, from all around the world.

Anyone can join.
Anyone can contribute.
Anyone can become informed about their world.

"United We Stand" Click Here To Create Your Personal Citizen Journalist Account Today, Be Sure To Invite Your Friends.

Please Help Support BeforeitsNews by trying our Natural Health Products below!


Order by Phone at 888-809-8385 or online at https://mitocopper.com M - F 9am to 5pm EST

Order by Phone at 888-388-7003 or online at https://www.herbanomic.com M - F 9am to 5pm EST

Order by Phone at 888-388-7003 or online at https://www.herbanomics.com M - F 9am to 5pm EST


Humic & Fulvic Trace Minerals Complex - Nature's most important supplement! Vivid Dreams again!

HNEX HydroNano EXtracellular Water - Improve immune system health and reduce inflammation

Ultimate Clinical Potency Curcumin - Natural pain relief, reduce inflammation and so much more.

MitoCopper - Bioavailable Copper destroys pathogens and gives you more energy. (See Blood Video)
Oxy Powder - Natural Colon Cleanser!  Cleans out toxic buildup with oxygen! 
Nascent Iodine - Promotes detoxification, mental focus and thyroid health.
Smart Meter Cover -  Reduces Smart Meter radiation by 96%!  (See Video)

Report abuse

    Comments

    Your Comments
    Question   Razz  Sad   Evil  Exclaim  Smile  Redface  Biggrin  Surprised  Eek   Confused   Cool  LOL   Mad   Twisted  Rolleyes   Wink  Idea  Arrow  Neutral  Cry   Mr. Green

    MOST RECENT
    Load more ...

    SignUp

    Login

    Newsletter

    Email this story
    Email this story

    If you really want to ban this commenter, please write down the reason:

    If you really want to disable all recommended stories, click on OK button. After that, you will be redirect to your options page.