Final answer:
Tropospheric temperatures have increased since the 1950s, with significant warming occurring especially since 1980, in line with higher atmospheric CO₂ levels.
Step-by-step explanation:
Since the 1950s, tropospheric temperatures have generally increased. Data from the National Oceanic and Atmospheric Administration (NOAA) and the National Aeronautics and Space Administration (NASA) reveal that Earth's surface temperatures have risen by more than one degree in the past 100 years, a trend that has been particularly pronounced since 1980. This warming pattern is closely linked to the enhanced greenhouse effect, driven by a rise in atmospheric concentrations of carbon dioxide (CO₂), which has increased from approximately 280 ppm in 1950 to 392 ppm by 2011.
Analyses demonstrate that the average annual temperature on Earth has been climbing for more than a century, with marked increases since the late 1800s. This warming is part of a broader set of changes, which have also resulted in shifts in global patterns of temperature and rainfall. Furthermore, the frequency and intensity of extreme weather events have also surged in some regions, suggesting an ongoing climatic transformation with multifaceted impacts.
Historically, prior to the late 1800s, Earth's climate saw significant fluctuations, with periods both colder by as much as 9°C and warmer by about 3°C in relation to current levels. Notably, atmospheric CO₂ levels have fluctuated between 180 and 300 ppm over these periods, emphasizing the strong correlation between CO₂ concentration and global temperatures.