Background
The authors note that "the recent increase in typhoon (tropical cyclone) activity has attracted great interest and induced heated debates over whether it is linked to global warming," adding that "skeptics of the global warming connection think that we are just at an active phase of multi-decadal variations in typhoons."

What was done
Fan and Liu present "a brief review and synthesis on the major research advances and findings of paleotempestology," which they describe as "a young science" that "studies past typhoon activity spanning several centuries to millennia before the instrumental era through the use of geological proxies and historical documentary records."

What was learned
First of all, the two researchers report that "typhoon-proxy data show that there does not exist a simple linear relationship between typhoon frequency and Holocene climate (temperature) change," noting that "case studies based on geological proxy records show that a warmer climate alone during the Holocene Optimum may not have increased the frequency of intense typhoons," and that "in the last millennium, the frequency of typhoon activity was not found to fluctuate linearly with climatic change over the centennial timescale." In fact, and "on the contrary," as they continue, "typhoon frequency seemed to have increased at least regionally during the coldest phases of the Little Ice Age." In addition, they report that "more typhoons and hurricanes make landfalls in China, Central and North America during La Niņa years than El Niņo years."

What it means
If anything, the world's climate alarmists seem to be claiming just the opposite of what is likely correct, as there would appear to be more tropical cyclone activity during colder as opposed to warmer times, on millennial, centennial and even yearly timescales.