In the image below from the National Snow and Ice Data Center you will see that the northern sea ice extent has been decreasing since at least 1980.
You also may want to click on the images to learn more if needed.
Now go to this excellent post byTim Lambert, or this little factoid on stratospheric cooling, and learn about the fingerprints that show the greenhouse signature, thus confirming the models. Take your time if necessary.
Groked it all?
Good. Then go to this tripe and detect 3 lies.