The impacts of climate change can be very rapid, as with the unexpected and precipitous decrease of arctic ice in recent years, erosion of low-lying coastal areas, and increased weather instability impacting traditional crops. While the planet is reckoning with the fastest climate change effects in its history, human impact on the environment has been occurring for millennia, and newer technologies can help scientists and historians discover, investigate, and make conclusions about ancient calamities.

In 2013, Professor Roland Fletcher, director of the Greater Angkor Project, gave the keynote talk for the Resilience and Sustainability: What Are We Learning from the Maya and Other Ancient Cultures? Symposium on the 2012 LiDAR (Light Detection and Ranging, an airborne laser system used to map sites without removing dense vegetation and other physical barriers) survey of Cambodia's Angkor site, which has given scientists fundamental new insights into the water crises of the 13th to 16th centuries, originally revealed at Angkor by a combination of dendrochronology and excavation. Tree rings have shown that from the early 14th century until the early 16th century Southeast Asia was experiencing extreme and unpredictable variability in the monsoons from mega-wet to severe drought. Archaeology has revealed alterations to the great reservoirs (baray) and damage to the southern canals of the network of Greater Angkor. Now LiDAR has shown that major defensive works were in progress and that severe erosion was occurring within the urban area. The significance of the demise of Greater Angkor is the insight it offers into the vulnerability to extreme climatic instability of giant low-density cities that are dependent on huge and intractable infrastructure.

Historical events that closely mirror current ones can be helpful in determining causality, effects, and possible ways to move forward; if nothing else they can demonstrate that regardless of era, human impact on local landscapes can irrevocably change those landscapes, cultures, and lives forever.