Context:

A new study has found that rising Carbon dioxide (CO₂) levels are linked to changes in rainfall and impacts on Biodiversity Hotspots.

More on the news:

• The research study was conducted by scientists from the Birbal Sahni Institute of Palaeosciences (BSIP) and was published in the journal Geoscience Frontiers.
• BSIP is an autonomous institute under the Department of Science and Technology.

Key Highlights

Impact of Greenhouse Gases on Equatorial Rainfall and Biodiversity

• The study has revealed that a global increase in greenhouse gases can lead to decreased rainfall in the equatorial region with associated shifts in vegetation
• It can also replace India’s biodiversity hotspots consisting of evergreen forests in the Western Ghats, northeast India and the Andamans with deciduous forests

Deep Time Hyperthermal Events as Climate Prediction Analogs

• Deep-time hyperthermal events are considered potential analogs for future climate predictions. 
• However, data on these events primarily come from mid- and high-latitude regions, with a significant lack of quantitative data from equatorial or tropical areas.

Research Methodology

• Researchers utilized fossil pollen and carbon isotope data from the Eocene Thermal Maximum 2 (ETM-2) to quantify the terrestrial hydrological cycle during that period.
• This period, also known as H-1 or Elmo (Eocene Layer of Mysterious Origin), is a period of global warming that occurred around 54 million years ago.

Significance of the Indian Plate

• During the ETM-2, the Indian plate was near the equator, making it an ideal natural laboratory to study the vegetation-climate relationship.
  The Indian Plate, a minor tectonic plate, originally part of Gondwana, which broke apart around 100 million years ago. It was during ETM-2 that the Indian plate lingered near the equator during its journey from the southern to northern hemisphere.
• Researchers selected the Panandhro Lignite Mine in Kutch, Gujarat, due to the availability of fossils from the ETM-2, and collected fossil pollen for analysis.

Significant Findings

• The analysis revealed that when atmospheric carbon dioxide concentration exceeded 1000 ppmv near the paleo-equator, rainfall decreased significantly. 
• This reduction in rainfall led to the expansion of deciduous forests in place of evergreen forests.

Implications for Future Conservation

• Research Published in the journal Geoscience Frontiers, raises critical questions about the survival of equatorial and tropical rainforests and biodiversity hotspots under increased carbon emissions. 
• Understanding the relationship between CO2 levels and the hydrological cycle can aid in the future conservation of these vital biodiversity hotspots.

Deep-Time Hyperthermal Events

• "Deep time hyperthermal events" refer to periods in Earth's distant past when the planet experienced significant and prolonged increases in temperature. 
• These events are studied because they can provide valuable insights and serve as models for understanding and predicting potential future climate changes. 

Biodiversity Hotspots

• Biodiversity hotspots are regions of the world that are exceptionally rich in plant and animal diversity but also face significant threats from human pressures. 
• There are 36 biodiversity hotspots, covering 2.5% of Earth's surface, but they support more than half of the world’s plant species as endemics — i.e., species found no place else — and nearly 43% of bird, mammal, reptile and amphibian species as endemics.