Climate change, yes its changing we are in an inter glacial period and the temperature still seems to be going up.
To me the question is : How much is due to human action? Fuck if I know but I doubt very much.
Do we have records? yes somewhat, do we have accurate records? fuck no. How accurate do you think you could be reading the temperature on a mercury thermometer 150 years ago? 50 years ago? how thick were the lines ? were they even printed on the glass or on a sheet of paper next to it? Were the instruments located exactly the same in all stations? Were they calibrated to an exact standard? Were the recording persons reading the same instrument at all locations? The answer is NO.
My hopes would be that we take care of what is easy and we aren't, there is more pollution from human shit in our water than you think, and plastics in the sea even though we, in the industrialized world are made to feel guilty about it, comes from the poorest nations. I've been there, traveled Asia in the 70's with the NAVY and I worked in different countries on occasion. In 2011 Vietnam, people were still piling up garbage along side the road and burning it because there was no collection, and that's a fairly organized country. So what do we do? we spend our treasure tilting at the windmill instead of picking up the horseshit in the middle of the road.