In these documents what are the enduring issue? The enduring issues are in the picture and I need a paragraph why they both are a certain enduring issue Document 1
Source: Monsoon records link demise of the Tang in China and Maya in Mexico, Michael Hopkin, Nature Magazine
They lived in resplendence, half a world apart, before meeting their respective downfalls within decades of one another. Now a new theory suggests that the decline of the Tang Dynasty in China and that of the Mayan civilization in Mexico may both have been due to the same worldwide drought.
Sediments collected from Lake Huguang Maar in southeastern China suggest that Asian summer monsoon rains were weaker during the eighth and ninth centuries AD, the time during which the Tang Dynasty faded from glory. And intriguingly, the same pattern is seen in sediments from the Cariaco basin off the Venezuelan coast, suggesting that a similar drought might have been occurring in nearby Mexico. The hardship caused by this drought could have been a key factor in the declines of the two cultures, they suggest.
At the moment, it is little more than a theory but the parallels are nevertheless notable. The Tang Dynasty, regarded as a high point in Chinese civilization, began to wane in the mid-700s and ultimately fell in AD 907 after a string of rebellions. Similarly, the Maya, who produced the earliest known written records in the Americas, numbered some 15 million in the middle of the eighth century, but had declined by three-quarters by AD 830, and left the last of their calendrical carvings in AD 909.
Failing summer rains might have contributed to these precipitous declines, notable historian Larry Peterson, of the University of Miami, Florida suggests. "The Mayan royalty were viewed as gods and were depended on to summon the rains," he says. Besides harming crops, the lack of rain might have damaged the leaders' credibility, he suggests. The timing of the declines and the climate changes make for a neat coincidence, but other factors cannot be ruled out, says Patrick Culbert, an anthropologist at the University of Arizona, Tucson. Drought was unlikely to have been the only factor in the cultures' declines, the Tang people, for instance, were hit hard by a military defeat by the Arab army in AD 751, which would probably have sowed unrest and rebellion. "I'm not saying they were keeling over from lack of water, but if the cultures were maxed out in terms of their environmental resources, it could have been a trigger," Peterson says.

Document 2
Source: Why does California have so many wildfires? Excerpt from the New York Times September 16th, Kendra Pierre-Louis and John Schwartz
Again, California is aflame — and it isn’t close to being over yet. As of Tuesday, more than two million acres have burned across the state so far in 2020, which makes this a record year, surpassing 2018, according to the California Department of Forestry and Fire Protection. About 200 Labor Day visitors to the Sierra National Forest had to be evacuated by helicopter after being trapped by the Creek Fire, and Governor Gavin Newsom declared a state of emergency in five counties.
High temperatures and strong winds have made the situation even worse. A heat wave baked Southern California over the weekend (Los Angeles County hit a record 121 degrees) and Death Valley recently reached 130 degrees, which, if confirmed, would be the highest temperature ever reliably recorded on the planet.
It’s counterintuitive, but the United States’ history of suppressing wildfires has actually made present-day wildfires worse. “For the last century we fought fire, and we did pretty well at it across all of the Western United States,” Dr. Williams said. “And every time we fought a fire successfully, that means that a bunch of stuff that would have burned didn’t burn. And so over the last hundred years we’ve had an accumulation of plants in a lot of areas. “And so in a lot of California now when fires start, those fires are burning through places that have a lot more plants to burn than they would have if we had been allowing fires to burn for the last hundred years.” In recent years, the United States Forest Service has been trying to rectify the previous practice through the use of prescribed or “controlled” burns.