Personal perspectives on weather control and modification...

The atmosphere and the myriad of weather conditions sprung forth across the planet ultimately touches all we do as a society. It accounts for the air we breathe and don’t think twice about, how long your commute to work was, the price of coffee, whether an afternoon can be spent at the park with your kids flying a kite, if a weather delay interrupts a sporting event, the historical battlefield conditions that in hindsight nudged the fate of war outcomes, et cetera. I challenge you to set a stopwatch for 5 minutes and list out how weather plays a role influencing your daily life. The list goes on and on! It is no wonder that the idea and perhaps the desire for the human species to ultimately control the weather has threaded itself throughout our history. Thoughts on manipulating the weather is not novel in today’s society.

The subject of weather modification is about as complex a topic as you can get when educating on atmospheric behavior and expectations. The reason is that such a conversation quickly exposes meteorology as an early and evolving scientific endeavor that is truly multi-disciplinary. For instance, the atmospheric system is interconnected to Earth’s three other primary geosystems (“hydrosphere” – concerning water cycles, “biosphere” – biomes and ecosystems that include society, and “lithosphere” – influences from Earth’s surface characteristics). Acknowledging meteorology as a young science lacking robust long-term weather data records with significant gaps in complete understanding is not necessarily a bad thing! Rather, it just points out a reality in the today and the ongoing challenge for current and future scientists willing to carry the proverbial torch.

The modern study of meteorology is a logical next evolution borne from other deep-rooted scientific disciplines with centuries of progress like chemistry, physics, and biology. Personally, I find this fascinating and one of the reasons I decided to pursue a career as a meteorologist. It really is by nature a massive interdisciplinary effort to unite current understanding drawn upon numerous field expert specializations for establishing the “hows” and “whys” of weather and climate. With that in mind, it makes sense that academic meteorology programs can be appropriately housed in “geography” departments at universities versus being separated by itself.

Weather modification is altering weather conditions that would have existed if not for an intervention (more perspective on this point in a bit). Changing the weather essentially means modifying a few key underlying meteorological concepts: 1) preexisting physical energy transfers and rates of transfers, 2) available environmental moisture content, and 3) enhancing or preventing the ability of water vapor in the air to generate either liquid droplets (condensation) or ice crystals (deposition). These three overarching concepts are intricately tied together and drive prevailing weather conditions around the world. So, has human society modified the weather. Absolutely! Once you consider the basic meteorological principles, evidence is everywhere you look.

First, let’s take a quick tour of historical endeavors. Have we made attempts at weather modification before? Yes! Some unusual examples in the late 19th and early 20th centuries include trying to prevent hail with cannons fired into thunderstorms or simply shooting supposed “rainmaker guns” into clouds to yield precipitation over drought-stricken areas. Obviously, these were mere hopeful attempts to change the local weather without scientific merit. More scientifically sound ideas arrived during and after the World War II era. For instance, in WWII British troops got creative burning fuel at airfields to create enough heat for unsaturating the air near the ground and, therefore, improve visibility for safer landings as dense fog evaporated away.

Probably the most well-known application, however, is the topic of cloud seeding, which started in the 1940s, as well. The basis for cloud seeding is knowing that water vapor in the air initially requires an existing physical platform called a “nucleation” site, or a “seed”, to begin condensing into a liquid droplet or directly turn to an ice crystal if cold enough. The atmosphere naturally has plenty of material (“seeds”) for water vapor to cling to. They include primary aerosols (dust, smoke, sea salt) and secondary organic aerosols (gaseous emissions becoming particulates after chemical reactions) from plant life (e.g., biogenic volatile organic compounds) and human activity (e.g., industrial emissions).

The key here to artificial cloud seeding is adding enough nucleation material to the existing atmosphere that already has higher humidity and sufficient cooling to encourage water vapor to phase change via condensation or deposition. Interestingly, it is reasoned that overseeding an active rainfall event (whether purposeful or ingested naturally by a passing storm) may initially reduce potential rainfall since abundant cloud condensation nuclei favors greater proportion of smaller droplet formation (larger drops and gravity are necessary to create downdrafts), but the influx of aerosols could prolong a storm and increase the liquid water loading content held in the storm cloud as it moves on. In any case, other important considerations of cloud seeding (again by natural means or human induced), include energy feedback changes by aerosols scattering incoming solar radiation from above (cooling process), cloud cover reflecting incoming solar radiation (cooling process) and both aerosols and clouds trapping long-wave radiation trying to leave the surface (warming process). I hope this mini-deep dive into cloud seeding begins to highlight how complex weather modification starts to become! A weather modification idea can quickly blossom into other important but not well understood environmental responses.

Our most evident environmental weather modifications are witnessed and felt near the surface and largely contained in what’s called the planetary boundary layer (see the previous discussion exploring why this atmospheric layer near the ground is especially relevant to us and the weather we experience). It turns out we are very good at making urban landscapes made of unnatural materials (concrete, asphalt, roofing shingles, et cetera). These types of materials collectively and significantly alter surface sunlight reflectivity (called “albedo”), possess a high heat trapping ability that becomes a source of warmth long after the sun has set, and generally lack moisture preservation properties. The result is the “urban heat island” effect; a warmer and drier climate.

Additional manmade weather modification examples (whether intentional or not) are creating reservoirs and neighborhood lakes to add available moisture to the air through evaporation (which also has a cooling effect), salting our roads to lower freezing points and preventing natural ice accumulations, erecting tall sky scrapers that change prevailing local wind patterns, converting natural landcover to large-scale farming and irrigation operations, creating artificial snow on mountains for ski resorts, deforestation affecting regional evapotranspiration rates and potential sources of natural aerosols, reshaping terrain to influence orographic precipitation, and adding heat in a local environment from numerous combustion engines in major cities that has a side effect decreasing humidity (same principle that the British military in WWII took advantage of to discourage fog formation). There are so many examples!

So, on local and regional scales weather modification is already quite common. Is it really possible, though, for society with purposeful intent to maneuver the globe’s entire atmospheric and connected systems in perpetuity at a wave of the hand? Perhaps one day, but unlikely any time soon. Furthermore, and vitally, if altered on such a grand scale could we know with certainty all deviations to expected weather at all corners of the planet that would have occurred otherwise? That point is really at the heart of the matter for discussions concerning controlling the weather and may in the end prove impossible to know once the system is “tampered” with in a significant way.

The fact is we can’t yet piece together precisely through space and time how the weather unfolds over the next week, let alone the next hour, in terms of a resolution that perfectly matches reality in retrospect. This is why post-forecast verification remains a necessary and integral part of today's weather prediction. In other words, surprises in weather behavior still occur and should be expected for the foreseeable future. This is not something to be discouraged about! There has been incredible research to date, leaps in technological innovations, data quality and resolution improvements, and message warning infrastructure put in place to help anticipate severe weather sufficiently in advance to preserve both life and property for many locations around the globe. That previous statement would have been less robust even just 10-20 years ago, so significant recent progress continues to be made. When it comes to confidence for global weather control, though, being able to answer would “this” have occurred if not for “that” becomes the litmus test. We are simply not there yet. Necessarily we continue to rely heavily on probabilistic approaches to guide future weather planning efforts. At this juncture, the known and still yet to be discovered complex atmospheric feedback loops coupled with our incomplete data observations across all location points at all times would undermine any plans for intentional and sustained large-scale weather controlling attempts.

Relevant to today, however, as the science becomes ever more robust society will gain greater clarity on precise cause-and-effect relationships and the resulting environmental ripple effects when collectively considered. Throughout this ongoing journey, research can better provide potential courses of action to take when unintentional weather modification becomes realized (e.g., addressing what role does large-scale and persistent influxes of greenhouse gases do to a closed planetary system).

Fundamentally, there should be caution for any weather control or modification discussion not objectively parsing out correlation versus causation. It is easy to associate something with another for the sake of proximity (i.e., correlation), but far more challenging using the scientific method and established peer review process to validate repeatable study outcomes meeting a statistical certainty threshold which then provide an acceptable measure of confidence for the scientific community to advance future studies upon.

To conclude, personally I believe weather is not something that should be tamed, rather weather represents a fluid reality to respect and evolve with. Afterall, the human species has already demonstrated remarkable adaptability to survive and thrive amongst Earth’s range of harshest climate types from sprawling metropolitans anchored in arid landscapes, high altitude oxygen deprived mountain ranges, coastal communities living with periodic devastating hurricane impacts, monsoon regimes where seasonal rain is measured in meters, and artic biomes that would test the hardiest of survivalists, to say the least. 

I have hope humankind endures in the face of current and future climate fluctuations. That being said, I believe actively discovering and appreciating how sensitive the planet’s linkages are between the atmosphere, hydrosphere, biosphere, and lithosphere at all scales represents a prudent mission for society to keep progressing towards. It makes sense there should be a sense of responsibility to deeply understand the implications our actions ultimately have affecting the one united global environment we call home.

Photo Credit: Jonny William Malloy