But the rate of extinction is far from constant.

但是灭绝的速度同一个恒定的常数有着相当大的距离。

youdao

Once forest cover does start increasing, the rate of extinction should dwindle.

一旦森林覆盖开始增加，灭绝的速度应该变小。

youdao

On the other hand, humanity's malignant effect on the environment has accelerated the rate of extinction for plants and animals, which now reaches perhaps 50,000 species a year.

从另一方面说，人类对环境的恶意影响加速了动植物的灭绝，现在每年大概有多达50,000种物种从地球上消失。

youdao

Some estimates suggest species extinction because of human activity is about 1,000 times faster than the natural rate of loss.

VOA: standard.2010.01.31