warning has just been issued by scientists to humanity

According to scientists, humanity should be concerned since 

the extinction rate of trees on Earth is approaching unheard-of proportions. For many years, 

the condition of the trees in our environment has been a persistent concern. 

But it appears that the problem is getting worse, and now we're dealing with a serious  

xtinction-level problem that might imperil entire ecosystems 

In the diverse ecosystems that make up our globe, trees are crucial 

State of the World's Trees, a report published by a group of scientists last year, 

examined how the extinction of particular tree species has impacted entire ecosystems. 

high temperatures in the city will have fatal effect