Many countries worldwide are still pushing for ‘Net Zero’ carbon dioxide emissions where any increase in the amounts emitted annually are sequestered at enormous expense. Unfortunately, the single-cause of weather and climate variability has been assigned to the infrared radiation energy interaction with the greenhouse gas GHG carbon dioxide CO2. Alas this fails to recognize that infrared radiation also impacts ALL the planet simultaneously; land, oceans, as well as a few atmospheric GHG’s.
Perhaps we should examine the massive ‘engineering-effects’ of mixing and turbulence, evaporation, phase change, simultaneous heat and mass transfer, molecular collisions, etc, rather than just single out infrared radiation and one ‘naughty’ greenhouse gas. There are many more mechanisms in play. Over 30 are presented here as examples.
Before we expand on those, we should review some key GHG interactions to show that they are very limited. A key foundational reason why the main GHG water vapour has been downplayed over decades is that much of the earlier literature, manuals, textbooks (even later the Web) have started with a dry atmosphere, simply because the concentration of aerial water vapour varied so widely worldwide. Even our school children were indoctrinated. Water vapour indeed is by far the strongest GHG and omitting that totally skews any analysis. It is over 1% of the atmosphere in New Zealand and around 4% in the tropics. All other GHG’s combined total less than 0.05% of the atmosphere worldwide. Hence focusing on CO2 as the culprit has mesmerized us from recognising that CO2 is the top ‘aerial fertilizer’ that has caused the massive recent increases in crop yields worldwide (20-30% increases on most crops over the last 3 decades). CO2 must also be applauded for the extensive ‘Global Greening’ phenomenon. Also CO2 is the main co-supplier of new oxygen O2 vital for life.
The natural photosynthesis process in all plants requires CO2, water, and sunlight to form glucose and all other complex organic chemicals (cellulose, dyes, flavours, juices, fruit, flowers, edible crops, and more). In the oceans (71% of the planet’s area) phytoplankton converts CO2 into shells and mollusks, while co-producing much of the world’s new O2requirement. But only 5% of all CO2 in the air is manmade, being produced mainly from industry, electrical power plants, and motor vehicles!
Sure CO2 is a GHG! But the atmospheric concentration of CO2 is very low at 0.042% (0.002% manmade portion)compared with water vapour at over 1%. Also the operating range of CO2 is so limited that it is wrong to elect it as a key weather parameter. For example, CO2 only has 2 bands (zones) for incoming solar, one of which is completely ‘swamped’ by water vapour (with 7 bands) at over 35 times the concentration. But it is not just the atmospheric concentration or amount because we must seriously consider molecular competition, simultaneous effectiveness of other GHG’s, and the uniqueness of water vapour which is the only gas that changes phase in air. The atmosphere is ‘loaded’ with unseen microdroplets of liquid water with additional heat transfer as well as mass transfer gradients across each-and-every drop. We now have an enormous number of additional mechanisms like vapour pressure differences, droplet surface tension and microthermal forces, and even sublimation, to name few. So why blame valuable CO2 and ‘bite the very hand that feeds us’? The competition is over!
Infrared radiation does not just ‘favour’ GHG’s but strongly interacts simultaneously and directly with the entire planet, land and sea.
DIRECT RADIATION to >>> LIQUID WATER [71% of the planet is ocean + cloud water droplets]
DIRECT RADIATION to >>> SOLID MATTER [29% of the planet is land and solid matter]
Only one atmospheric gas directly above the land and sea changes phase; water vapour. Sea, lake, and river water can evaporate and condense to form massive amounts of microdroplets, mists, fogs, and clouds. Also these droplets can transform to solid ice particles and snow and can go straight back to vapour water without going through the liquid phase (termed sublimation). Most, if not ALL these processes, are NOT GHG-radiation processes. These additional mechanisms must be seriously considered as potentially active weather-changing interactions over and above the radiant energy-GHG phenomenon.
These will be briefly considered under FIVE headings.
1. EVAPORATION:
(a) 71% of the Earth’s surface area is ocean. Incoming solar radiation directly impacts LIQUID water as oceans, lakes, and rivers. 423 trillion tonnes of water evaporate/ year (13 million tonnes/second). This evaporation is caused mainly by direct solar energy absorption to surface liquid water [NOT a greenhouse-gas effect]
(b) Liquid water can evaporate without external solar radiation (energy can come from within the liquid itself causing liquid water evaporative-cooling) [NOT a greenhouse-gas effect]
(c) Liquid water can evaporate into the atmosphere even when there is no temperature difference between the water layer and atmosphere (with or without solar radiation-water absorption) (Reason: When the atmosphere is not saturated with water vapour ie partial pressure lower than the vapour pressure) [NOT a greenhouse-gas effect]
(d) Liquid water can evaporate into the atmosphere in certain cases when the air near the interface is at a lower temperature (no external solar radiation needed) (partial pressure lower than the vapour pressure) [NOT a greenhouse-gas effect]
(e) Liquid water can evaporate into the atmosphere when the air flowing across the interface is not already saturated with water vapour (a concentration driving force: not a temperature driving force) [NOT a greenhouse-gas effect]
(f) Liquid water evaporation into the atmosphere can be augmented just by an increase in interfacial surface area: waves, winds, impacting raindrops, and other surface flow disturbances [NOT a greenhouse-gas effect]
(g) Temperature gradients immediately below the liquid ocean surface can cause convective liquid-mixing / microturbulence and thermal gradients, augmenting evaporation and thus the production of water vapour [NOT a greenhouse-gas effect]
2. ATMOSPHERIC HUMIDIFICATION – WATER VAPOUR CHANGES
(a) Water vapour can move in air without radiation due to differences in pressure, humidity (water vapour concentration), humidity, and/or air density (non-thermal driving forces). Convection and diffusion occur [NOT a greenhouse-gas effect]
(b) Water vapour concentrations in the atmosphere can change due to the interactions of adjacent moving air having different levels of moisture-vapour content (humidity difference). Examples: breezes, winds, thermals, gales [NOT a greenhouse-gas effect]
(c) Water vapour concentrations can change in the air due to the local presence of liquid water; water droplets, mists, rain, fogs, ice crystals etc [NOT a greenhouse-gas effect]
(d) Water vapour concentrations in the atmosphere can change when water vapour sublimates and goes directly from gas to ice or snowflakes [NOT a greenhouse-gas effect]
(e) Water vapour concentrations can change in the air when the water vapour-liquid water equilibrium (dew point) exceeds its natural limit [NOT a greenhouse-gas effect]
(f) Water vapour concentrations can change in the air when that moist air comes into contact with cooler solid surfaces e.g. condensing as dew [NOT a greenhouse-gas effect]
3. CONDENSATION in the ATMOSPHERE
(a) Gaseous water vapour and/or existing liquid water molecules can aggregate or combine to form small liquid droplets in clouds, mists, or fogs [NOT a greenhouse-gas effect]
(b) When atmospheric water vapour condenses to form fogs, mists, or clouds (phase changes), it gives up large amounts of thermal energy as latent heat [NOT a greenhouse-gas effect]
(c) Liquid water in clouds, mists and fogs can evaporate back again to form water vapour (gas) if the air is not saturated with water vapour [NOT a greenhouse-gas effect]
(d) Liquid water in clouds, mists and fogs can evaporate to form water vapour (gas) with-or-without a temperature change (concentration-difference driving forces) [NOT a greenhouse-gas effect]
(e) Gaseous water vapour can condense and molecules amalgamate with either, other existing water vapour molecules, and/or, other liquid water molecules to grow clouds, mists or fogs
[NOT a greenhouse-gas effect]
(f) Gaseous water vapour can transform straight to ice crystals or snow particles without going through the liquid phase (sublimation: latent heat transfer) [NOT a greenhouse-gas effect]
4. PRECIPITATION
(a) Miniscule water droplets can aggregate to form larger, less-buoyant water droplets, that can then fall by gravity as rain to cool the air, then sea and land [NOT a greenhouse-gas effect]
(b) Water droplets can freeze and amalgamate to form larger, less buoyant ice and snow particles which can and precipitate towards the planet’s surface, cooling the atmosphere, land, and sea [NOT a greenhouse-gas effect]
(c) Large falling rain droplets can pass through a cold atmospheric layer and freeze to form ice crystals or snow particles(radiation is not required) [NOT a greenhouse-gas effect]
(d) Snow particles / ice crystals can melt and produce cold liquid rain drops by energy absorption, or transfer straight to water vapour (no radiation) [NOT a greenhouse-gas effect]
(e) Raining water droplets can vaporise to form water vapour (gas) either by thermal energy transfer or by mass transfer driving forces (unsaturated local atmosphere) {termed ‘virga’: visible rainfall does not actually reach the ground} [NOT a greenhouse-gas effect]
(f) Falling ice and snow particles can, by sublimation, transfer directly to gaseous water vapour (radiation is not required) [NOT a greenhouse-gas effect]
5. OTHER FACTORS
(a) Water vapour concentration normally decreases as temperature decreases. But it can either decrease or increase in concentration without any temperature change. Adiabatic humidification can occur (examine a Humidity Chart). These mechanisms do not require solar radiation directly, and are not widely understood or used [NOT greenhouse-gas effects]
(b) Massive convective mixing operations occur worldwide in rain, winds, gales, storms, hurricanes, and more. They must be factored in. Thermal driving forces caused by temperature differences or mass transfer driving forces caused by concentration, humidity or density differences, can all affect weather-changes: [NOT greenhouse-gas effects]
(c) All air molecules impinging on solid and liquid surfaces transport both thermal and kinetic energy to and from the surfaces. Direct solar energy can heat planet earth and all solid materials on it so that air impinging on a surface is ‘excited’, moves to heat other fluid molecules, and/or re-radiate longer-wave thermal energy [NOT greenhouse-gas effects]
Most importantly overall, it must be seen that there are not just temperature-gradient driving forces (heat transfer), but also concentration-humidity driving forces (mass transfer driving forces), momentum driving forces (kinetic energy transfer) as in convective bulk mixing, and others like pressure differences and vapour pressure and density-difference driving forces. These additional mechanisms cut right across the false notion that water vapour concentration depends only on temperature-rise which could possibly be caused by other non-condensable GHG’s and radiation. Even NASA misses this point in some published web articles, as the water / water vapour system is seen only to be a passive feedback GHG system (not a non-forcing action), caused by the earth heating up. In some cases (Wikipedia), water vapour is wrongly excluded as an active and controlling GHG altogether. In reality, it is by far the strongest GHG. Wikipedia is therefore incorrect in reporting that.
It is scientifically inaccurate and dishonest to isolate “radiation-low concentration / non-condensable GHG’s like CO2 and CH4”, without fully endorsing: 1. Direct radiation - LIQUID water interactions; 2. Direct radiation – SOLID matter exchanges; 3. Radiation - water vapour excitations; 4. All the other thermal and non-thermal humidity driving forces in winds, thermals, gales, rain, storms, hurricanes, tornadoes, Trade Winds, Jet streams, El Nino’s, La Nina’s, atmospheric pollution, and incomplete combustion particulates. All are significant! The impacting effects of ocean currents, ocean conveyor belts, cloud dynamics, the moon in elliptical orbit, solar wind, sunspot activity, and more, must also be added as very important drivers in all weather-change operations.
It is no wonder that simplified mathematical models fail to grapple with all these additional mechanisms in climate-change scenarios, and therefore their predictions and even models can be seriously erroneous. This is made worse by almost completely ignoring phase change (change-of-state) [liquid water >>> water vapour > >> liquid water >>> solid ice crystals >> liquid water or vapour directly]. The liquid water- vapour water system is the self-compensating, self-regulating, self-buffering, and self-restoring that moderates the entire world ecosystem.
Dr Geoffrey G Duffy DEng, PhD, BSc, ASTC Dip., FRSNZ, FIChem E is a Professor Emeritus of Chemical Engineering at the University of Auckland.
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