RealClimate: Unforced Variations: Apr 2023

Tomáš Kalisz says

3 Apr 2023 at 9:27 AM

@ms,

I would like to respond also to your comment on my post of March 30 (I am new here and do not see an option how to reply to this older comment directly).I exploit the circumstance that you touch the same topics – the role of latent heat flux and the intensity of water cycle in climate regulation.

macias shurly says

1 Apr 2023 at 11:43 AM

@Tomáš Kalisz says: –

." We emphasize that our goal here is not to obtain an accurateestimate of global transpirational cooling, but to present plausible arguments showing that it can be large.

Therefore, by construction, globalclimate models cannot provide any independent information about the climatic effect of evapotranspirational cooling "

ms: — Hello Tomáš Kalisz – I am a biologist and artist and I looked at your graphic about heat wave mitigation / global water cycle restoration. dr Gavin Schmidt is hard to reach when it comes to evapotranspiration and ecology. I’ve been posting on more or less the same topic for many months and it's hard to have fact-based communication. Broad sections of the audience here are convinced that water cycles should only be seen as feedback on higher GHG emissions. A theory according to which man has actively interfered with the water cycle for thousands of years and actively impeded evaporation – they reject.

So don't let that unsettle you. Of course, the water cycle plays the primary role in regulating the Earth's temperature. According to the IPCC, on agricultural and forestry areas and urban land areas land use change has decreased evaporation extensively on 72% (94 million km²) of the ice-free land area (130 million km²).

BOX | BREAKDOWN OF THE GLOBAL, ICE-FREE LAND SURFACE (130 MILLION KM2)72% of land directly affected by human use:–37% of pastures, of which 16% are used savannahs and shrublands, 19% extensive pastures and 2% intensive pastures (since 1961, the number of people living in areas affected by desertification almost tripled).22% of forests, of which 20% are managed for timber and other uses and 2% are planted12% of cropland, of which 10% are non-irrigated and 2% irrigated (since 1961, the use of fertilisers increased by nearly ninefold and the use of irrigation water doubled.1% of settlements and infrastructure

28% of unused land:–9% of intact or primary forests7% of unforested ecosystems, including grasslands and wetlands (since 1970, wetland areas have declined by 30%).12% of barren wilderness, rocks, etc.

Thank goodness the IPCC at least recognized in 2021 AR6 that irrigation has a cooling radiative forcing, even if IMHO the value is far too low and cooling through the albedo change of land use change is a very questionable matter in particular.

https://upload.wikimedia.org/wikipedia/commons/thumb/a/a0/Physical_Drivers_of_climate_change.svg/450px-Physical_Drivers_of_climate_change.svg.png

Since the loss of evaporative landscapes cannot be denied (nor can the GHE of CO2) a value for this loss is missing in the 200 times peer reviewed graphic (@ Dan).

The following graphic is the combination of a GEB model with the observation values CERES 2000-2020, which also quantitatively captures the loss of evaporation and the 20-year development of the global climate. Less evaporation (-0,86W/m²) —> less cloud albedo (~ -0,8W/m²) are the main driver of the increased energy imbalance.

https://climateprotectionhardware.files.wordpress.com/2023/03/geb_2000-2020finish.png?w=1024

I also really like the project of conquering/populating the desert with solar cells.However, at the moment it seems that the production of electricity via mirror power plants and concentrated solar radiation in combination with a steam turbine has better efficiency, since the electricity production can be sustained at night by thermal storage.

But you probably know that cooled PV modules show an improved power production with every °C of cooling (~0.5%/°C). A PV module that is cooled down from 95°C to 35°C, for example, produces ~ 30% more energy and is certainly more durable. I myself develop prototypes in the field of *water-cooled LED light and PV-T modules with ~85% efficiency". If you are interested – just contact me.

Mirror power plants are very expensive in terms of production costs – which not every desert state can afford. PV systems in the desert require significantly less effort, time and capital.If I understand your graphic correctly, you want to evaporate water with hot solar cells ????

(TK) My comment amendment thereon is as follows:

I am a physical and organic chemist by my education and a technologist and patent engineer in several chemistry-related industry branches by my career. Being since 2011 in organic semiconductor industry and dealing also with materials for organic solar cells, I strived to grasp in which extent might photovoltaics (and organic photovoltaic as a part thereof) contribute to a switch of electricity production from non-renewable sources to renewable ones.

Although my primary focus is on electrochemical technologies for a cheap long-term electricity storage that might make electricity production from intermittent renewable sources such as wind and sun reliable and still cheap enough to be economically competitive with fossil fuels, see e.g.https://orgpad.com/s/5BfLP-cxj-7 ,I see as potentially important also the questions pertaining to economy and possible environmental consequences of massive renewable source exploitation.

As you may take from the link https://journals.ametsoc.org/view/journals/hydr/23/1/JHM-D-20-0266.1.xml (also saved in the orgpage https://orgpad.com/s/VhvfDd5uRIP you looked at), some models predict that making a hot desert even hotter by lot of waste sensible heat released from classical solar panels should paradoxically bring more precipitation thereto.

This prediction is exactly opposite to the assumptions of the biotic pump hypothesis assuming that for bringing moisture from the ocean to the interior of continents, an intensive small water cycle enabled by forests and wetlands should be beneficial.

The idea behing my proposal is testing both hypotheses practically, on urban islands as a model of a desert, by installing either lot of classical solar panels, or (togerther with a necessary infrastructure for rain catching and storage) "2.0" solar panels cooled by water transpiration. A statistical evaluation of both alternatives could show if rather the first or the second alternative brings more precipitation into hot cities and makes the conditions therein more livable during the hot summer seasons.

The results migh then serve as a testing benchmark for the respective microclimate models.Finally, the results of such comparisons could be perhaps exploited also for testing the available global climate models.

I hope that although Dr. Gavin Schmidt may not become impressed, someone else from the climate modelling community might perhaps still perceive this idea as worth of an attention.