In the past few decades, the warmest period in 2000 has declined, and the worrying rate has exceeded 98%. Earth surface. This is the conclusion of researchers of long-term temperature trends in nature and natural earth sciences.
The “Little Ice Age” lasts from about 1300 to 1850 and is usually depicted as an era when even large areas of water were frozen and used as roads, and glaciers extended to mountain valleys. At that time, the unusually cold weather in Europe lasted for hundreds of years. Climate historians pointed out that this was due to the analysis of tree rings and other sources, not to mention the style paintings of that period.
Similar conclusions apply to North America. Therefore, it is assumed that the Little Ice Age and the best period of the earlier medieval climate (the warming period, which is mainly known from Europe and North America, occurred around 800-1300) is a global phenomenon.
But now, an international team of researchers led by Raphael Neukom of the Climate Change Research Center of the University of Bern (Switzerland) has a completely different view of climate change.
After analyzing the climate change over the past two thousand years, scientists said in the “Nature and Natural Geosciences” that there is no evidence that periods of warming or cooling have occurred simultaneously on a global scale.
Raphael Neukom quoted on his university website: “It is true that in the Little Ice Age, the earth was generally colder. -” But not everywhere, and not at the same time. The peak periods of warming and cooling in the pre-industrial period occurred in different places and at different times. “
For example, the lowest temperatures in two millennia were taken in time and space: in the 15th century, they occurred in the central and eastern Pacific, in the 17th century in Northwest Europe and North America (in the southeast), and in the 19th century. . Already everywhere. Similarly, in the early stages of industrialization, the heat trend was not consistent. To be sure, the warmest period of the past 2,000 years has declined in the past few decades, covering more than 98%. Earth surface.
According to climatologists, incorrect assumptions about the simultaneous climatic phases on the planet are only the result of our selective knowledge-when it comes to climate history in Europe and North America, it must be more detailed.
In the absence of data from other parts of the world, the conclusions of the two continents are extended to other parts of the earth. Based on this, it is assumed that the relatively cold or warm period in 2000 is a global phenomenon. However, the author of the new analysis emphasized that this is not the case.
Researchers now published in the journal Nature suggest that in certain periods before industrialization, periods of warming or cooling were mainly the result of natural climate fluctuations. External factors, such as volcanic eruptions or solar activity, are not strong enough to cause significant warming or cooling of the entire planet for decades or even centuries.
To study the five pre-industrial eras, scientists used the database of the International Research Association PAGES, which provides climate data for the past 2000 years. The historical climate data comes from other analysis of tree rings, the ice extracted from the sediments at the bottom of lakes or coral reefs that constitute polar regions (the “deeper” ice formed there hundreds or even thousands of years ago) A study of the gas content of bubbles in the core. The authors of “Nature” used up to six statistical models to analyze these data, which can estimate the temperature and the probability of extremely high or low temperatures, even decades or even centuries.
As a result, the authors of the study concluded that if you look at climate change from a global perspective, you will not be able to find a single, coherent picture of the various historical periods studied. Neukom said: “The minimum and maximum temperatures are different in different regions.”
Since the 20th century, we have been observing the only very warm period that affects the entire planet (98% of its surface). Year-the scientist emphasized.
According to experts, this alone can prove that modern climate change is unprecedented and cannot be explained by natural climate change alone. To understand these climate changes, one must consider the anthropogenic emissions of carbon dioxide and other greenhouse gases.
In the 20th century, not only was the global average temperature higher than ever before, reaching level 2,000. Years, and the warming period also covers the entire planet. The rate of heating is unprecedented.
PAP-Science of Poland