Global annual mean surface temperature change

The graph shows global annual mean surface temperature change from 1880 to 2020. The temperature anomaly begins at -0.2 degrees Celcius in 1880 and dips down to -0.4 degrees by 1910, but then raises steadily to around zero by 1940. From 1940 to 1980 it averages around zero, but then increases steadily all the way to 2000.

NASA GISS

Line plot of global mean land-ocean temperature index, 1880 to present, with the base period 1951-1980. The dotted black line is the annual mean and the solid red line is the five-year mean. The green bars show uncertainty estimates. [This is an update of Fig. 1A in Hansen et al. (2006).]  Data for this graph come from https://data.giss.nasa.gov/gistemp/graphs_v3/