A warming climate may have enabled the earliest humans to venture into Western Europe 1.4 million years ago , a new study suggests . Researchers believe that the spread of our distant human ancestors , the hominins , had been halted by colder and drier temperatures . But as conditions warmed , they were able to branch out from Africa into Spain , and ultimately spread across Europe . Spanish researchers say climate change impacted human migration . Until 1.4 million years ago it was too cold to inhabit southeast Spain . But then the climate warmed to 13°C ( 55°F ) and became more humid . This enabled hominins ( stock image shown ) - our distant ancestors - to move to new regions . The research was led by Dr Jordi Agusti from the Catalan Institution for Research and Advanced Studies ( ICREA ) . Published in the Journal of Human Evolution , the paper suggests climate change affected the amount of resources available . There have been various theories put forward over the years about the diet of our early ancestors , but a study from Oxford University published last year claimed to have finally settled the debate . An ancient human ancestor known as ‘ Nutcracker Man ’ lived mainly on a diet of tiger nuts , worms and grasshoppers , according to research . Scientists believe this diet explains why the ancient hominin relative , called Paranthropus boisei , which lived in East Africa between 2.4 and 1.4 million years ago , had such distinctively powerful jaws and large , flat molar teeth . The theory is based on analysis of the Barranco León site in the Guadix-Baza Basin in southeast Spain . Here , simple Oldowan tools have previously been found , linked to the earliest known hominins 1.4 million years ago , reported Popular Archaeology . But they were not able to migrate to this region until conditions improved . The researchers said that the early Pleistocene era ( the era lasted from 2.59 million to 11,700 years ago ) was characterised by colder and drier weather . This ‘ possibly impeded the settlement of this region by the early hominin population from the southern Caucasus , ’ the researchers wrote . But shortly afterwards , ‘ when the climatic conditions were again favourable , a hominin presence is suddenly evidenced. ’ The theory is based on analysis of the Barranco León site in the Guadix-Baza Basin in southeast Spain , shown by the grey marker on this map . Here , simple Oldowan tools have previously been found , linked to the earliest known hominins 1.4 million years ago . The Acheulean tool technology period - between 700,000 an 300,000 years ago - followed the more primitive Oldowan period . Tools at the time included large stone hand axes ( stock image shown ) made from flint and quartzite , used to scavenge from carcasses . It should be noted that the warming climate referred to here is on a vastly longer time scale than modern climate change . At the time 1.4 million years ago , though , temperatures warmed above 13°C ( 55°F ) and humidity increased , allowing hominins to inhabit the region - scavenging carcasses in the region with the help of tools . ‘ The data reported here clearly support the idea that the early hominin occupation of Europe was strongly constrained by climatic and environmental conditions , rather than by physiography or cultural factors , ’ the researchers wrote .
Spanish researchers say climate change impacted human migration . Until 1.4 million years ago it was too cold to inhabit southeast East Africa . But then the climate warmed to 13°C ( 55°F ) and became more humid . This enabled hominins - our distant ancestors - to move to new regions .