Global warming? Yea, but...

As little as 30 years ago the talk wasn’t about
global warming, it was about an imminent ice age.
Is an ice age likely? Even possible? Consider
this: There have been more than 20 glacial
advances, or ice ages, in just the last two
million years. And we know from geological
evidence that each glaciation lasted anywhere
from 20,000 to 100,000 years—no one knows why the
disparity—separated by warm periods that last
some 10,000 to 15,000 years. What we can be
reasonably sure of is that we’re now in one of
the warm periods, and this one is already 13,000
years old. Some scientists think it’s at an end
and a new ice age is about to begin.
...
But we now have evidence that ice ages come on
with an abruptness that will catch us by total
surprise. Physical evidence indicates that when
the last ice age started, the British Isles went
from a temperate climate to being completely
covered with glaciers hundreds of feet thick in
just 20 years.

Do scientists think it’ll happen that way again?
Yes. And if the next ice age starts here’s how it
may occur: At first we wouldn’t even realize it,
so the first few years we’d feel we were just
having one or two bad winters. But after a few
years rivers will freeze all-year-round, snow
from the previous years won’t completely melt,
glaciers will begin to form, and some of what is
currently now the world’s most fertile ground
will become unfarmable.

Makes a lot of sense to me.

On the other hand, it may take awhile to occur.

Read.