Dust from asteroids entering the atmosphere may influence Earth's weather more than previously believed, according to an article in the journal Nature. Researchers have found evidence that dust from an asteroid burning up as it passed through Earth's atmosphere formed a cloud of micron-sized particles large enough to influence local weather in Antarctica, where glaciers are rapidly melting. Particles this size are large enough to reflect sunlight, causing local cooling and playing a major role in cloud formation. The dust can even have a negative effect on the ozone layer. This may temporarily help reverse the rapid melting of the Antarctic.
I like the idea that some of this infalling dust contains "extremophile" microbes that we've ignorantly assumed to be native to Earth.