Studies show that Arctic warming is rapidly transforming tundra vegetation. Existing plants are growing taller and greener, and new, taller shrub species are moving into regions that were previously too cold. The change, known as shrubification, is a major climate change indicator.
The greening does not simply offset warming. The extra plant growth absorbs more carbon dioxide, but other effects of the shrubs push temperatures up further.
The Arctic tundra has historically supported only miniature plant life. Extreme winter cold and strong winds limit growth, and shallow permafrost, the permanently frozen subsoil, restricts deep roots.
The region is now warming four times faster than the rest of the planet, an effect called Arctic amplification. Alaska's North Slope, for instance, has warmed by about 2.7°C over the last 40 years, primarily because of fossil fuel emissions. Rising temperatures are letting existing Arctic plants grow taller and allowing new, taller species to move in.
Taller, darker shrubs protrude above the white snow and so reduce the surface albedo, or reflectivity. A surface that reflects less sunlight absorbs more solar radiation, which traps heat and accelerates warming in the Arctic.
Shrubs also trap more snow. The snow insulates the ground beneath, and the warmth lets soil microbes stay active through the winter. They release higher levels of methane, a potent greenhouse gas.
The added greenery helps absorb more carbon dioxide, a natural carbon sink effect. That benefit is heavily offset by the warming from reduced albedo and methane release.
The expansion of shrubs such as willows creates more shade over streams. This alters the local habitats and ecology of native fish, insects and birds.
Scientists are also rethinking evolutionary survival in the Arctic, asking how species cope with the severe stress of climate change. They suggest that plant species rely on mutualism, or cooperation among species, rather than cutthroat competition to survive.
With reference to the spread of shrubs in the Arctic tundra, consider the following statements:
Which of the statements given above are correct?
Consider the following statements:
Statement-I: The Arctic tundra has historically supported only miniature plant life.
Statement-II: Extreme winter cold and strong winds limit plant growth, and shallow permafrost restricts deep roots.
Which one of the following is correct in respect of the above statements?
Consider the following pairs:
Term : Description
How many of the above pairs are correctly matched?
