Know Climate Change

Impacts of Climate Change

Impacts on Ecosystems

Dying ecosystem in Alpine Mountains
due to global warming


With the increasing pressure of human induced changes, ecosystems will be further fragmented, and there will be degradation of natural habitats. This will alter the structure, reduce biodiversity and perturb functioning of most ecosystems, and compromise the services they currently provide (IPCC, 2007).

Increased CO2 level in the atmosphere is causing acidification in oceans. This is a major threat to the marine life.

Findings from Research

  • Several terrestrial ecosystems act as major carbon sinks (contributing to the uptake of GHGs). These ecosystems are vulnerable to climate change and/or land-use impacts. Scientists have projected that their capacity utilization will peak before mid-century, and they are then likely to become a net carbon source by 2100 and will amplify global warming, as there will be more GHGs emitted than absorbed.
  • Roughly 20%–30% (with the spread among regional biotas being from 1%–80%) of species assessed so far (in an unbiased sample) will be at increasingly high risk of extinction as global mean temperatures exceed 2–3 °C above pre-industrial levels (the industrial period refers to 1870 onwards). Global losses of biodiversity are extremely alarming as the process of extinction is irreversible.
  • There will be substantial changes in structure and functioning of marine and other aquatic ecosystems due to mean global warming of more than 2-3 °C above preindustrial levels and the associated increase in atmospheric CO2 levels (IPCC, 2007). This will lead to ocean acidification and impair a wide range of marine biodiversity. Progressive acidification of oceans is expected to have negative impacts on marine shell-forming organisms like corals and their dependent species.

Climate Change: A Threat to Coral Reefs
Reefs are habitats for about a quarter of marine species...

Reefs are habitats for about a quarter of marine species and are the most diverse among marine ecosystems. They play a very important role in coastal protection, fisheries, tourism and comprise a critical food and income source in the developing countries. Rising sea surface temperature leads to bleaching of the corals (loss of algal symbionts).

Rising CO2 concentrations also affects corals by declining their calcification and weakening their coral skeleton. Increased concentration of CO2 has led to decrease in the oceanic pH and to a lower level of pH than experienced over the past 20 million years.

If the same continues there will be huge losses of coral reefs, and by 2070, it may reach a state of significantly reduced coral cover and greater erosion of reef frameworks.