Yes, climate knows no boundaries. What happens in the Artic, Antarctic or tropics effects us thousand of miles away in many ways. The fact that climate is far different around the globe is why we measure the temperature of the earth by taking the average of thousands of weather station around globe. These averages are used to form a global temperature of the earth each year. The result for a single year has no significance but when compared to previous years, it shows a clear trend of rising global temperatures over the last 60 years. Temperature measurement over 100 years ago has shown increases in temperature but lack the confidence of the later measurements due less weather stations and poorer equipment and procedures.
Studies of tree rings and artic ice allow us to determine changes in temperature that goes back over a hundred years. The confidence in these studies are not near as good as actual temperature measures but they do show lower average temperatures 100 and 200 years ago.