Our directory of things of interest

University Directory

Eastward expansion: why the 100th meridian is on the move

American farmland (such as this one in South Dakota) could find itself being restructured as climate conditions move humid conditions more towards the east of the country American farmland (such as this one in South Dakota) could find itself being restructured as climate conditions move humid conditions more towards the east of the country
02 Jun
2018
As climate conditions at the 100th meridian, the traditional United States boundary between the humid east and the dry west, are shown to be on the move, could it mean a reshaping of America’s farmlands?

 In 1878, explorer John Wesley Powell travelled east to west across the US and noticed a change in the plants around him. Over a relatively small transect of land, prairie flowers gave way to drier shrubs, which in turn gave way to cacti. This gradual but strong transition, between the humid east and the dry west, extended in a straight line from north to south of the US, roughly following the 100th meridian. New research has now confirmed that this climate divide is gradually moving towards the east.

The divide can be seen from space, on Google Earth, and ‘is also plain to window seat passengers flying on airplanes across the continent’ say researchers from the the University of Columbia who have been looking into this territorial shift.

Though scientists largely agree that the climate divide along the 100th meridian exists, the Columbia study is the first to examine its causes. By looking at precipitation models, the team discovered the divide occurs for three reasons: the east is kept wetter by winter storms from the Atlantic and summer storms from the Gulf of Mexico that bend northeast. Meanwhile storms from the Pacific are wicked away by the Rocky Mountains, leaving the west dry.

us mapThe climate divide is readily visible on maps of the US

According to the findings, these dry conditions are moving eastwards. By analysing climate data from 1979 to 2015, the researchers found there had already been a noticeable trend eastwards of the arid climate, now putting the divide roughly at the 98th meridian. ‘There have also been contributions from declining precipitation but we think those might mostly be due to natural variability,’ says Richard Seager, lead author of the study. He believes it is rising temperatures that will increase evaporation and move the arid conditions further eastward. By linking these findings with climate change models, the team predicts that the easterly trend will continue to become more noticeable throughout the 21st century.

If the predictions become true, it could amount to big repercussions for land use along the 100th meridian. Already farming is largely dictated by the divide: moving west across it, farms become fewer and larger by land area, reflecting less available quantities of water. The majority of crops also change from moisture-loving corn, to plants that cope better with dry conditions, such as wheat. The researchers predict that these characteristics will need to be incorporated into the land around the 98th meridian in order to handle the warming conditions to come, potentially redrawing the agricultural maps of North and South Dakota, Nebraska, Kansas, Oklahoma and Texas.

This was published in the June 2018 edition of Geographical magazine

red line

NEVER MISS A STORY

Geographical Week

Get the best of Geographical delivered straight to your inbox by signing up to our free weekly newsletter!

red line

Related items

Subscribe to Geographical!

Geographical Week

Sign up for our weekly newsletter today and get a FREE eBook collection!

University of Winchester

EDUCATION PARTNERS

Aberystwyth University University of Greenwich The University of Derby

TRAVEL PARTNERS

Ponant

Silversea

Travel the Unknown

DOSSIERS

Like longer reads? Try our in-depth dossiers that provide a comprehensive view of each topic

  • The Human Game – Tackling football’s ‘slave trade’
    Few would argue with football’s position as the world’s number one sport. But as Mark Rowe discovers, this global popularity is masking a sinister...
    Essential oil?
    Palm oil is omnipresent in global consumption. But in many circles it is considered the scourge of the natural world, for the deforestation and habita...
    The Nuclear Power Struggle
    The UK appears to be embracing nuclear, a huge U-turn on government policy from just two years ago. Yet this seems to be going against the grain globa...
    National Clean Air Day
    For National Clean Air Day, Geographical brings together stories about air pollution and the kind of solutions needed to tackle it ...
    The Air That We Breathe
    Cities the world over are struggling to improve air quality as scandals surrounding diesel car emissions come to light and the huge health costs of po...

MORE DOSSIERS

NEVER MISS A STORY - Follow Geographical on Social

Want to stay up to date with breaking Geographical stories? Join the thousands following us on Twitter, Facebook and Instagram and stay informed about the world.

More articles in NATURE...

Energy

The Treasury has announced that it is considering imposing a…

Tectonics

Major earthquakes are triggering seismic activity half the world away

Climate

Marco Magrini finds that a warming world also means a…

Wildlife

Unchecked tourism is potentially reducing the number of cheetah cubs that…

Oceans

A relocated military base in Okinawa, Japan will cause ‘irreversible’…

Climate

The ongoing recovery of the planet’s ozone layer is being…

Oceans

The Ocean Cleanup has launched System 001, a floating barrier…

Nature

New videos reveal how plants respond to wounds, sending forth…

Geophoto

The recent heatwave had everyone longing for a drop of…

Wildlife

The demand for horseshoe crab blood – vital for testing…

Climate

One of the problems in getting accurate climate science out…

Wildlife

Italy is divided over the future of its wolves and…

Energy

A Scottish tidal power project in the Pentland Firth has…

Oceans

The world’s first full global analysis of beaches reveals the…

Geophoto

With the recent Saddleworth Moor fire, it can be easy…

Wildlife

Whale sharks have been found to not travel far from…

Wildlife

The Lone Star tick is spreading across North America, carrying…

Tectonics

Earlier this week, Indonesia was struck by a series of…

Energy

Efforts to reduce the energy drain of the internet are…

Energy

Coal’s rising popularity among climate-apathetic leaders is a worrying trend,…