Everyone is so fierce about global warming, but you must be happy that icebergs in the Arctic and Antarctica are melting, right? If they wouldn’t melt, at some point the entire ocean will close up and the ice will reach the land and only then will we have an ice age. That’s right isn’t it?
Answer
Dear Tessa,
Icebergs come from ice caps. These mostly grow on land: Greenland, Alaska, Antarctica… and reach far out to sea, but they mostly still rest on the shallow seabed. When the bottom gets really deep (deeper than 1000 m), you will no longer find ice caps. So ice sheets grow from land to sea.
You will find sea ice at sea, such as at the North Pole (this is a frozen sea). And this can also get quite thick. During colder periods such as ice ages, the ice caps on land will continue to grow and the sea ice will also become thicker and more abundant.
We are now living in an inter-glacial period. About 2 million years ago we entered a period where ice ages and interglacial periods alternate. One cycle, from ice age over interglacial to the start of the next, lasts about 100,000 years. So if the climate remains as it is now, we will enter a new ice age within a few thousand years. So you and your later children, grandchildren will not experience that yet.
What is the effect of global warming on this? Honestly? No one knows for sure… We are probably still heading for an ice age, but it will be a little less cold.
Should we be happy with the current warming? I don’t think so, just think about all the effects of global warming: rising sea levels, extinction of species, periods of drought… This will all happen gradually, and we will suffer from it faster than an ice age. And if it’s cold, we can always put on a thick sweater and cozy up by the fire ;-).
Answered by
Prof. dr. Dr. David Van Rooy
Marine geology (sedimentology, paleoceanography, micropaleontology, deep-water ecosystems)
http://www.ugent.be
.