Climate Change Impact on India and World – International Reports, Key Observations, etc.



From UPSC perspective, the following things are important :

Prelims level : Dendrochronology

Mains level : Bio-indicators

Reconstructions of past responses of vegetation from different ecosystems can predict the impact of climate change on weather and other environmental parameters.


  • It is the study of tree rings that hold a wealth of information about not only a tree’s past but also that of the ecosystem in which it lives.
  • Tree rings are layers of growth that a tree acquires in a year.
  • The colour of old wood is always darker than a comparatively newer wood which creates a contrasting pattern of rings year on year.
  • In the years of good growth, characterized by a healthy supply of resources, the ring is thick.
  • It is thin when the ecosystem has dearth of resources.
  • Trees can be great records for past and recent climates, much better than climate records as their density in a region is much greater than climate observatories and their information close enough to actual conditions.

How does Dendrochronology help?

  • As trees are sensitive to local climate conditions, such as rain and temperature, they give some information about that area’s local climate in the past.
  • For example, tree rings usually grow wider in warm, wet years and they are thinner in years when it is cold and dry.
  • If the tree has experienced stressful conditions, such as a drought, the tree might hardly grow at all in those years.
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