According to the National Climate Assessment, heatwaves were much worse in the US prior to 1960.
Temperature Changes in the United States – Climate Science Special Report
Data from the EPA shows the same thing.
“For the last twenty-five years or so the average temperature of the United States has been growing warmer, the average rising about one degree every four years. …. Heat and drought reached their peaks in. the disastrous summer of 1934.”
– New York Times December 16, 1934
TimesMachine: December 16, 1934 – NYTimes.com
Unadjusted temperature data from NOAA shows that the US was much warmer and drier prior to 1960.
ftp://ftp.ncdc.noaa.gov/pub/data/ghcn/daily/ghcnd_hcn.tar.gz
Burn acreage was much higher prior to 1960.
2010-sustainability-report.pdf
TimesMachine: October 9, 1938 – NYTimes.com
Burn acreage correlates well with hot summer temperatures.
Glaciers in Glacier National Park retreated rapidly from 1850 until about 1960, but now are growing.
Recent Glacier Recession in Glacier National Park, Montana on JSTOR
29 Dec 1923, Page 5 – at Newspapers.com
12 Apr 1924, 7 – Spokane Chronicle at Newspapers.com
17 Sep 1936, Page 16 – Arizona Republic at Newspapers.com
05 Mar 1952, Page 1 – The Post-Standard at Newspapers.com
Swiftcurrent Glacier
Grinnell Glacier
The Aspen Daily Times January 16, 1936 — Colorado Historic Newspapers Collection
19 Feb 1937, 11 – The Evening Sun at Newspapers.com
17 Dec 1939, Page 15 – Harrisburg Sunday Courier
13 Oct 1910, Page 7 – Aberdeen Herald
02 Nov 1922, Page 1 – Great Bend Tribune at Newspapers.com
National Geographic Magazine Archive
The Present Climatic Fluctuation on JSTOR
SUNDAY, DECEMBER 7, 1958
SEVERAL thousand scientists of many nations have recently been climbing mountains, digging tunnels in glaciers, journeying to the Antarctic, camping on floating Arctic ice.
Glaciers in the western United States, for example, have lost 50 per cent of their ice in seventy years. The floating ice of the Arctic is one-third thinner and covers a considerably smaller area than it did sixty years ago.
TimesMachine: December 7, 1958 – NYTimes.com
15 Apr 1934, Page 33 – The Lincoln Star
Berkeley Earth has erased all of the warmth prior to 1960. Fire and ice don’t lie, but climate scientists do.
