 This figure from the IPCC starts back in 1850 and then runs up to just past 2000 up here on the right and it shows indications of warming happening in the climate system. You can see on top here the thermometer record of global average temperature showing not much happening and then recent warming very clearly. Sea level, which is given here, rises because ocean water expands as it warms and because warming tends to melt glaciers that are holding water out of the ocean. And so we see a warming influence that shows up in the rise in global sea level. And we also look, if you go to springtime, snow cover, you can see that not much was happening and then you can see it dropping and that's happening because of warming and the spring is melting the snow. And so these are among many indicators that are showing that yes, the climate system is warming.