The unsubstantiated claim has been that human CO2-induced climate change was (and is) producing dramatic changes in precipitation levels across the world.
But is it true?
A research effort was undertaken to determine if indeed the evidence backed up the alarmist non-empirical claims/predictions.
The study's findings:
"...report that "most trends exhibited no clear precipitation change," noting that "global changes in precipitation over the Earth's land mass excluding Antarctica relative to 1961-90 were estimated to be: -1.2±1.7, 2.6±2.5 and -5.4±8.1 percent per century for the periods 1850-2000, 1900-2000 and 1950-2000, respectively." ... "stations experiencing low, moderate and heavy annual precipitation did not show very different precipitation trends," ... "deserts/jungles are neither expanding nor shrinking due to changes in precipitation patterns." ... "reasonable to conclude that some caution is warranted about claiming that large changes to global precipitation have occurred during the last 150 years."
Simply put, the exaggerated climate change claims of major disruption to rainfall/snow patterns are just that, exaggerations sans any empirical evidence. The evidence-based science is clear: Over the last 150 years, precipitation trends remain within normal variability.
Prior climate/weather change and peer-reviewed articles.