Please note that the 30 yr trend between 1910 and 1940 is very close to identical to the trend between 1970 and 2000. (culturalcognition.net)
Rejects the null hypothesis that the latest observed 20 - yr and 30 - yr trend of near - surface temperature (ending in 1994) is part of natural variability with a risk of less than 2.5 % to 5 % (climatesignals.org)