The oceans at the beginning of the 20th century (1900-1930) were warmer than previously thought.
During this period, the ocean appeared colder due to the way some measurements were taken. This is evidenced by the results of a new study by scientists from the University of Leipzig (Germany), the university’s press service reports.
In this way, researchers have found an explanation for why climate models and measurements show a consistent pattern of global warming on land and oceans between 1850 and 1900, but in subsequent decades an unexplained “cold period” occurs in the oceans.
The discovery was made as scientists worked to reconstruct average global temperatures based on historical climate data, including historical land and ocean measurements, as well as paleoclimate analysis.
Comparing land and ocean, they noticed a systematic deviation:
- at the beginning of the 20th century. ocean temperatures were cooler than in previous decades, while air temperatures over land remained relatively constant;
- This result is inconsistent with physical theory and climate models.
The new study shows that ocean surface reconstructions of global average temperatures over this period are too cold: on average about 0.26 degrees Celsius colder than land-based reconstructions. This discrepancy is greater than what would be possible with natural climate variability, the article states.
The reason for this was the measurement methods that were then used.
There are established approaches to accounting for the influence of the configuration of measurement methods on ocean surface temperature measurements. The new study shows that in the early 20th century, these methods did not adequately account for the rapidly changing differences in the way observations were made, the paper says.
The fact is that before World War II, ocean temperatures were mostly measured using buckets on ships, but the method of measurement and the composition of the ship fleet varied from decade to decade, making it much more difficult to correct for systematic measurement errors.
At the same time, scientists note that this discovery generally does not change ideas about long-term warming since 1850 and the role of people in it, but it allows us to better understand historical changes and clarify climate models.
The causes of the warming period between 1900 and 1950 have never been fully understood.
The glaciers of Antarctica have already been actively melting in the recent past.
Source: Racurs
I am David Wyatt, a professional writer and journalist for Buna Times. I specialize in the world section of news coverage, where I bring to light stories and issues that affect us globally. As a graduate of Journalism, I have always had the passion to spread knowledge through writing.