If another mega drought hits the US Southwest, this one will allegedly be your fault, because (cough-mumble)

Millions of trees will die | Payson, AZ

The strongest mega drought in the record dates back to the second half of the 1200s and probably played a role in the collapse and abandonment of ancient cultures throughout the Southwest.

Another prolonged, severe drought occurred in the late 1500s. Virtually every tree studied from that period showed years of narrow growth rings, together with a massive die-off across the region. The forests rebounded when normal rainfall resumed in the early 1600s.

“Following the 1500s’ mega drought, tree rings get wider and then there was a major boom in new trees. Nearly all trees we see in the Southwest today were established after the late-1500s drought, even though the species we evaluated can easily live longer than 400 years. If forest drought stress exceeds late 1500 levels, we expect that a lot of trees are going to be dying.”

Unfortunately, the team’s climate prediction models suggest that within the next 40 years the region will fall deep into mega drought conditions. The models predict that even the wettest, coolest years in the late 21st century will exceed mega drought levels. In that case, the drought conditions of the past decade will prove the new normal rather than a bad stretch.