The 1st episode of 2.
The 2nd one can be found here:
Experts keep telling us that man is directly responsible for global warming, yet most
of us carry on doing precisely the things that are driving climate change. But when
the peerless David Attenborough looks out of your TV screen and asks, "How could I
look my grandchildren in the eye and say I knew about this [climate change] - and I
did nothing?" it makes you stop and think. In the conclusion of his two-part film,
he discovers that the Earth's future could be very bleak. If CO2 reaches a particular
level in the atmosphere (the "tipping point"), we could lose entire ecosystems such
as the Arctic, while entire cities - such as London - could be drowned by its melting
ice. It's not too late to do something, though. Fictional family the Carbons show us
where we're going wrong and what we can do to put it right.