Here are a few links to web sites that contain up-to-date crucial observations.
In my opinion one of the most important is ocean heat content. The reason is simple. The ocean’s heat capacity is enormous. It takes up almost all of the additional heat the Earth accumulated in the last decades. Here is the image and link:
I think the 0-2000 m figure is the most interesting because it shows that the Earth’s climate system has not stopped warming 10 or 15 years ago as some claim. The “global warming hiatus” does not exist.
My second favorite must be the Mauna Loa CO2 record. Image and link here:
The monthly mean data displayed there by default show that we almost hit the 400 ppm mark in May of 2013. No doubt that we will exceed it this spring.
Next: Arctic Sea Ice. The National Snow and Ice Data Center has this great interactive graphic, where you can click on individual years and compare to the average. Image and link here:
And for the final observation: Global surface temperatures. Image and link here:
If you pull down the “Timescale” menu and select “annual” you’ll get the annual mean. Will 2014 hit a new record high?
It is worthwhile checking back once-in-a-while with these great web sites.