Climate change is one of the most formidable challenges of the 21st century and global warming is its driving force. While human activities exacerbate global warming, natural climatic shifts have occurred for centuries. One such shift was the last global warming period. But what is the exact date of this event?
The answer to this question is not a straightforward one. Over the past centuries, climate variation has been observed but the start and end dates of the last global warming period still remain disputed. Denialists point to temperature readings from the end of the 19th century to assert that temperatures haven’t been steadily climbing since then. This is not an accurate assessment, however, as this data does not include the entire picture.
A more accurate assessment of global temperature can be gleaned from studying different climate records such as polar ice cores, tree-ring width chronologies, and cave stalagmites. All of these sources provide overlapping yet distinct records, allowing for analysis on which to build more comprehensive climate models. These analyses, combined with evidence of past changes in ocean currents, suggest that the last global warming period occurred in the early 20th century.
It is generally accepted that the global climate was relatively stable until the mid-1970s. From then until the present, global temperatures have been increasing steadily. This period of warming, spanning around 40 years, represented the last true global warming period. A few studies suggest that the warming began even earlier, with the onset of the industrial revolution in the mid-19th century. However, this is a more contested hypothesis.
The last global warming period had a dramatic effect on the environment. Tree cover in many countries decreased, and desertification was seen in many parts of the world. Scientist Robert Berner documented an increase in the rate of sea-level rise during this period. Sea ice in the Arctic and Greenland started to melt at an alarmingly rapid rate, and mountain glaciers retreated significantly. The adverse effects of this warming period have impacted both humans and wildlife.
It is difficult to determine the exact start and end dates of the last global warming period, but the overall effect of this period on the climate is undeniable. Human activities have played an undeniable role in global warming, but it is clear that climate has shifted naturally throughout history. The decrease in tree cover, increase of sea levels, and melting of ice sheets would not be possible without some type of previous warming period, and this calls for further research on the exact moment when the last global warming event occurred.
Global warming is not only an issue of the present but one that affects our past, present, and future. We must remain vigilant in understanding the impact our actions have, and continue to research the history of global climate cycles in order to ensure a more stable future.