• Skip to primary navigation
  • Skip to main content
  • Skip to footer
Zippy Facts Logo

Zippy Facts

Interesting Random Facts

  • Animals
  • Culture
  • Firsts
  • Food
  • Geography
  • Health
  • History
  • Inventions
  • Language
  • Mythology
  • Odds
  • People
  • Religion
  • Science
  • Space
  • Universe
  • World
You are here: Home / Science / Why Is the South of Britain Sinking and North Britain Rising and What Causes the Earth’s Crust To Sink?

Why Is the South of Britain Sinking and North Britain Rising and What Causes the Earth’s Crust To Sink?

March 28, 2020 by Karen Hill

Yes, it is true that South Britain is sinking. It’s the result of a process called isostatic rebound.

Since the last ice age, a huge burden of ice has been removed from the north of Britain.

Because the Earth’s crust is not rigid, as it appears to us over a human lifetime, but very slightly elastic, it gradually responds to the addition or removal of weight above it by sinking or rising.

This adjustment takes thousands of years.

If you remove, say, a layer of rock 1,000 feet thick from the crust, this will rise some 650 feet, just as removing cargo from a boat will make it rise higher in the water.

Ice is about a third the density of crustal rock, so removing 1,000 feet of ice will cause the crust to rise around 200 feet or so.

Scandinavia and Scotland were under more than 1,000 feet of ice during the ice ages, and uplift here is fastest in the northern Baltic, where it still continues at nearly three feet per century.

This is easily noticeable even over a human lifespan. The Hudson Bay area of Canada experiences a similar rate of uplift, for the same reason. In Britain the process is fastest in northeastern Scotland, where raised beaches exist several yards above the present sea level.

So why is the south of England sinking? First, the burden of Scottish ice pushed up the crust in surrounding areas that were ice-free, just as pressing down one part of a water bed makes adjacent areas of it rise.

That process is now in reverse: the once-raised regions of southern England and the southern Baltic are now sinking.

Secondly, sea level is rising worldwide.

Once it rose rapidly as the ice sheets over places like Scotland melted. Now global warming may be melting glaciers, sending more melt- water into the oceans. As the oceans grow warmer, thermal expansion also raises sea level.

So the south of England gets a double whammy, sinking crust and rising sea level. Without rising sea levels, the line between the sinking and rising parts of Britain would run between Wales and Yorkshire. Because of the latter, the line is further north, near the border of England and Scotland.

Regarding vulnerability to marine flooding, the London area is subjected to a quintuple whammy.

Apart from the two factors above, the Thames Valley is a syncline, an area of locally subsided crust. Also, until recently groundwater extracted from below London was causing further subsidence.

Finally, the funnel shape of the North Sea tends to bank up storm surges to ever greater heights as they enter the Thames Estuary.

All this adds up to one inescapable fact: the lower Thames was not a good place to site a major capital city.

As the south of England sinks, the sea is rising to engulf it. Also, thermal expansion of the oceans is increasing the depth of the sea by about 3 millimeters a year.

In Essex, in the southeastern corner of Britain, the net effect of sinking and rising water is a relative sea level rise of 6 millimeters a year.

This is of huge concern to conservationists, coastal landowners, and those charged with maintaining sea defenses.

Related Facts

  • How Cold Is the South Pole and Why Is It Colder At the South Pole Than At the North Pole?
  • How Did Land On Planet Earth Develop and How Did Volcanic Activity and Basalt Help Create the Earth's Crust?
  • Why Is the Moon So Much Bigger When It's Rising and Setting On the Horizon?
  • What Is the Difference Between the United Kingdom and Great Britain and Is Ireland Part of Great Britain?
  • Do More People Live In North America Than In South America and How Large Is the South American Continent?
  • Where Is the North Star, What Is the Name of the North Star, and Will the North Star Always Be the Polestar?
  • Why Do the Remains of Buildings From Ancient Civilizations Sink So Far Below the Surface of the Earth?
  • When Earth's magnetic field reverses will compasses point South instead of North?
  • Why Is the City of Venice In Italy Slowly Sinking Into the Sea and How Do People In Venice Get Around?
  • Why Is New Orleans Sinking and How Much Land In New Orleans Is Lost To Water Each Year?
  • How did the crew on the Titanic discover that the Titanic was sinking?
  • How Do Fish Stay Suspended In Water Without Sinking or Floating?

Filed Under: Science

About Karen Hill

Karen Hill is a freelance writer, editor, and columnist. Born in New York, her work has appeared in the Examiner, Yahoo News, Buzzfeed, among others.

Previous Post: « How Does NASA Brew Beer In Space, What Does Space Beer Taste Like, and How Do You Drink a Coke In Space?
Next Post: If the Earth Was Shrunk To the Size of a Squash Ball Would It Be Smoother Than a Squash Ball and Why? »

Footer

Follow

  • Facebook
  • Flickr
  • GitHub
  • Google+
  • Instagram
  • LinkedIn
  • Medium
  • Pinterest
  • StumbleUpon
  • Tumblr
  • Twitter
  • YouTube

Categories

Accomplishments Animals Culture Firsts Food Geography Health History Inventions Language Mythology Odds People Religion Science Space Universe World Your Body

About

Zippy Facts empowers the world by serving educational content that is accessible to everyone.

A tribute to growing up, zippyfacts.com showcases interesting and unusual facts about the world.

Our mission is to use technology to facilitate knowledge transfer and sharing.

Copyright © 2021 Zippy Facts

  • About Us
  • Contact
  • Privacy Policy