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Climate change is impacting the structure of Earth's atmosphere

  • Category
    Geography
  • Published
    16th Nov, 2021

Context

A recent study suggests that climate change is causing a significant impact on the ‘structure of the Earth’s atmosphere.

Background

  • The study considered decades of weather balloon observations and specialized satellite measurements.
  • Based on these observations and measurements, scientists determined how much the top of the lowest level of the atmosphere is rising.

Analysis

Understanding Earth’s atmosphere

  • Earth’s atmosphere is very thin, with a mass of only about one-millionth that of the planet itself.
  • Earth’s atmosphere has five major and several secondary layers. From lowest to highest, the major layers are the
    • Troposphere
    • Stratosphere
    • Mesosphere
    • Thermosphere
    • Exosphere

Layers

Location

Function

Troposphere

Extends from Earth’s surface to, on average, about 12 kilometers (7.5 miles) in height, with its height lower at Earth’s poles and higher at the equator.

  • It holds all the air plants need for photosynthesis and animals need to breathe.
  • It also contains about 99 percent of all water vapor and aerosols (minute solid or liquid particles suspended in the atmosphere).

Stratosphere

Located between approximately 12 and 50 kilometers (7.5 and 31 miles) above Earth’s surface

Known as home to Earth’s ozone layer, it protects from the Sun’s harmful ultraviolet radiation

Mesosphere

Located between about 50 and 80 kilometers (31 and 50 miles) above Earth’s surface, the mesosphere gets progressively colder with altitude.

  • The top of this layer is the coldest place found within the Earth system.
  • The very scarce water vapor present at the top of the mesosphere forms noctilucent clouds, the highest clouds in Earth’s atmosphere.
  • Sounding rockets and rocket-powered aircraft can reach the mesosphere.

Thermosphere

Located between about 80 and 700 kilometers (50 and 440 miles) above Earth’s surface

  • Temperatures increase with altitude due to the very low density of molecules found here.
  • It is both cloud- and water vapor-free.
  • The aurora borealis and aurora australis are sometimes seen here.
  • The International Space Station orbits in the thermosphere.

Exosphere

Located between about 700 and 10,000 kilometers (440 and 6,200 miles) above Earth’s surface

  • This layer doesn’t behave like a gas, and particles here escape into space.
  • While there’s no weather at all in the exosphere, the aurora borealis and aurora australis are sometimes seen in their lowest part.
  • Most Earth satellites orbit in the exosphere.

What has been found?

  • They found that the tropopause region is pushing up the boundary with the Stratosphere by about 50-60 meters (about 165-195 feet) per decade. 

Tropopause

The tropopause is the upper limit of the troposphere and therefore constitutes the boundary between it and the Stratosphere.

Depending on the season, it ranges from about 5 miles above Earth’s surface at the poles to 10 miles at the equator.

About 80 percent of the atmosphere is contained within its lowest layer, the troposphere.

The location of the tropopause is of interest to flight crew because it indicates the altitude at which temperature becomes constant with increasing altitude, which is an essential factor in performance and fuel calculations.

It also indicates the location of jet streams and the high winds and turbulence associated with them.

What is responsible for this change?

  • This rising is caused by warming temperatures near Earth’s surface, causing the lower atmosphere to expand.

Conclusion & Way forward

Unfortunately, greenhouse gas emissions from human activities are going to affect Earth’s climate for decades and even centuries. In addition to this, humans will keep on adding carbon dioxide to the atmosphere at a rate far greater than it is removed by a natural process, thus creating a long-lived reservoir of the gas in the atmosphere and oceans.

In the coming decade, climate change will particularly depend on the number of greenhouse gases emitted into the atmosphere and how much they get absorbed by the ocean, the biosphere, and other sinks. It will also depend on how sensitive Earth’s climate is to those emissions.

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