Asian Monsoon Almost 40 Million Years Old

A new study suggests that Asian monsoon - one of the largest climate system in the world - existed much earlier than previous estimates.

According to University of Arizona geoscientists, Asian monsoon was in place 35-40 million years ago, which is around 15 million years before than other estimates about its origin. The climate system began at a time when atmospheric carbon dioxide was roughly three to four times greater than it is now. Asian Monsoon then lost its intensity around 34 million years ago.

Previous research had suggested that the climate system originated due to topographical reasons such as the uplift of the Tibetan plateau and the Himalayas.

Asian monsoon brings rainfall and dry winter to a significant part of the continent. The study also shows that an increase in atmospheric CO2 will affect rainfall in several countries.

"This finding has major consequences for the ongoing global warming," lead author of the study Alexis Licht, now a research associate in the UA department of geosciences, said in a news release. "It suggests increasing the atmospheric CO2 will increase the monsoonal precipitation significantly."

The study is published in the journal Nature.                               

In the latest study, the researchers were actually looking at fossils of ancient animals from Southeast Asia to understand prehistoric climate conditions. The team expected that several of these ancient animals lived in relatively mild pre-monsoonal conditions. What they found instead, was that several creatures lived in intense climatic patterns, with heavy rains and dry winters.

"The early primates of Myanmar lived under intense seasonal stress - aridity and then monsoons. That was completely unexpected," Licht said in a news release.

The team analyzed 40-million-year-old freshwater snail shells and teeth from mammals to analyze the type of oxygen that these animals were using. The ratio of oxygen-18 and oxygen-16 shows whether the creature lived in wet or arid climate.

Asian monsoon generates wind patterns in winter that blow dust from Central Asia and deposits it in China. A team of scientists working in China found these dust particles in some regions dated back to 41 years ago, showing that the climate pattern is much older than previous estimates.

Each year, torrential rains during monsoon bring life to fields parched by several dry days of summer. This year, the rains in India came late, but have been so intense that the Kashmir valley submerged in water. The heavy downpour has resulted in some 400 deaths in India and Pakistan.

Stanford scientists have earlier warned that monsoon rains have become infrequent and that central India is at a higher risk of experiencing severe flood and drought in the near future.