The Global Land-Sea Temperature index from 1880-present from NASA and GIS:

"Except for a leveling off between the 1940s and 1970s, Earth's surface temperatures have increased since 1880. The last decade has brought the temperatures to the highest levels ever recorded. The graph shows global annual surface temperatures relative to 1951-1980 mean temperatures. As shown by the red line, long-term trends are more apparent when temperatures are averaged over a five year period. Credit: NASA/GISS"