Department of Social Sciences

  • Research_OutOfAfrica_banner_jpg
  • Climate change: the key to human expansion

    Changes in climate which led to sea levels being over 100m lower than today would have narrowed a crossing point between Africa and Arabia for our species.

    Climate change: the key to human expansionProfessor Adrian Parker specialises in long-term climate change cycles, focusing on the patterns of change around North Africa and Arabia over the past two million years and their potential impact on human migration.

    The region fluctuated between very wet environments to the arid landscape we know today.

    To produce accurate timescales of these fluctuations Professor Parker looks for changes between aridity and wetness and tries to reconstruct ancient climates.

    Plummeting sea levels

    One of the biggest impacts of climate changes is on sea levels. Sea levels were about 100m lower than present day levels during ice ages when a third of the earth’s surface was covered in ice and up to half was desert. As ocean levels rise and fall, land is submerged and then exposed.

    The Bab al Mandab Straits at the southern end of the Red Sea that today separate Yemen from Africa could have been a passable route during a period of low sea levels at the end of one ice age.

    As the Earth warmed and became wetter, there would be a lag between the ice melting and sea levels rising. During this phase Arabia changed from being largely arid to being rainier and more fertile.

    This new fertile land would allow humans to migrate, and whilst the sea levels were low, they could travel to new locations before sea levels rose again.

    The changing climate

    Professor Parker’s long-term findings have shown there are natural cycles that tell us the Earth's climate is dynamic, variable and constantly changing.

    I strongly believe we need to be better custodians of our planet – but global climate change is not solely caused by humans. There are natural cycles that show us the Earth’s climate is dynamic. Our emergence as a species appears to be largely driven by climate and environment.

    Understanding past climates may also help inform us about how we can prepare for the future.

    Professor Adrian Parker