I understand that icebergs are brought to earth from outer space. Basically salt water that has been traveling through deep space, got cold , froze, then struck earths oceans and have been happily floating about ever since. Now that brings me to my primary concern, global warming! !!!! Because of global warming the suns temperature is steadily rising and having a dramatic effect on the planets orbiting the sun. The alarming thing isn't rising sea levels (as we can just build boats), the REAL danger from the melting icebergs is what alien microbiological threats are being freed from the the ice as it melts !!!! Alien microbiological pathogenesis being released into our oceans on a daily basis. NO THANK YOU! Who knows what life these icebergs have picked up whilst travelling through deep space!!! It's frankly frightening. .it's only a matter of time before a deadly pathogen is released and cause an extinction event. Why is not more being done about this!?!?!
You understand incorrectly. It isn't known for certain where the water on Earth originated, but it is a popular hypothesis that at least some of it came from extra-planetary bodies hitting Earth at some point. That probably wouldn't have been salt water as we think of it today (though it would likely have lots of other materials in it) but either way, it certainly wouldn't come down as icebergs. Any water that did come to Earth this way will have likely melted and frozen multiple times over the subsequent millions of years. That said, there is a potential concern with much more recent (on a planetary scale) pathogens the originated on Earth and were trapped in ice more recently (like the last Ice Age) and could be released if that ice melts. They wouldn't necessarily be harmful to us directly, but there could also be concern about other species too. There are scientists researching exactly this though, you just don't hear about it because it's not the kind of thing that is media friendly.
