From the graph given in the question, it can be observed that the average surface temperature of earth sees a steady increase after the year 1960. Before 1960, it can be seen that the average surface temperature is almost the same.

The increase in the average surface temperature of earth can be attributed to the increase in global warming. This is caused due to the significant increase in the levels of carbon di oxide in the atmosphere.

Conclusion:

Yes. The average surface temperature of earth has been increasing over the past 150 years.