Question

Usable direct measurements of earth's surface temperature go back to approximately ________

a. 1850
b. 1997
c. 400,000
d. 1725
e. 1952

Answer 1

Direct measurements of Earth's surface temperature date back to approximately 1850, with data indicating an increase in annual mean temperature and a general long-term warming trend.

Step-by-step explanation:

Usable direct measurements of Earth's surface temperature go back to approximately 1850 (Option a). The observational data and direct measurements in the provided figures demonstrate a record of global surface temperature since the late 19th century. These records, such as the global land-ocean temperature index depicted in Figure 24.9.3, show an increase in the annual mean temperature relative to mid-20th-century baseline values. Furthermore, this trend is supported by data from the National Oceanic and Atmospheric Administration (NOAA) and the National Aeronautics and Space Administration (NASA), which confirm that the Earth's surface temperatures have risen over one degree in the past 100 years.