[This is true. Jan]
A research team of the University of Cologne in Germany has published an open access paper arguing that a series of cold, dry phases during the last European ice-age triggered the demise and finally lead to the extinction of Neanderthals in Europe.
The oldest evidence of any hominids in Europe date back 700,000 to 600,000 years ago. At that time, Europe was covered in forests, with many large animals, like elephants, rhinoceroses, horses, deer and large bovines, roaming free. As prey species were abundant, different subspecies of the genus Homo could coexist contemporarily. From 350,000 to 40,000 years ago Neanderthals (H. neanderthalensis) became the dominant human species in Europe.
As during the ice-age, starting some 125,000 years ago, the climate cooled and Central Europe became inhospitable, they survived in refugial areas located along the southern borders of the European continent. In the next 60,000 years the climate oscillated between long, cold phases and short warm intervals. Pollen analysis shows that during the cold phases the forests, covering the continent during the warm intervals, were quickly replaced by a shrub-filled grassland.
Some 43,000 to 40,000 years ago sites with artifacts by Neanderthals disappear from the archaeological record, to be replaced by the culture of the Aurignacian, characterized by artifacts (like stone tools, prehistoric art and even musical instruments) attributed to the modern human species H. sapiens. Analyzing the chemical properties of annually deposited layers of stalagmites from two caves in modern Romania, the scientists were able to reconstruct the climate in Central and Eastern Europe between 44,000 and 40,000 years ago.
A drop in global temperatures marks the beginning of the last ice-age some 125,000 years ago. 70,000 to 60,000 years ago the climate temporarily stabilizes, becoming warmer again. 50,000 years ago, as the large ice-shields of North America melted in response to the warming climate, a large quantity of freshwater flowing into the Atlantic Ocean slowed down the oceanic currents. As those currents are important to carry warm water and air towards Europe, the continent experienced a chaotic pattern of cooling phases interrupted by short, dry pulses. The studied cave deposits show two pronounced cooling episodes 44,000 to 43,000 and 40,800 to 40,200 years ago. 42,000 ago also the climate in Europe became much drier. In response the forests covering most of the continent were quickly replaced by grassland. The last traces of Neanderthals are found before this phase. During the cold and dry phase any signs of human activity disappear completely. When the climate warms again new artifacts appear in the archaeological record, attributed to modern humans. The research argues that in the cold, dry grassland also large animals were rare. Neanderthals, a society of specialized hunters, would have faced a hard time to survive without large preys to hunt. Unlike previous cold phases, also this time the southern refugial areas were occupied by a new human species, as modern humans were migrating from the Near East into Europe. The already small populations of Neanderthals were forced to stay in the tundra and unable to hunt there large prey, they numbers quickly dwindled. Finally Neanderthals went extinct 40,000 years ago. The now empty landscape was quickly claimed by modern humans, migrating from the southern borders into the heart of Europe, as the climate became more hospitable again 40,000 to 35,000 years ago.
As compelling this scenario appears, some unanswered problems remain. Neanderthals were one of the most successful human species, surviving more than 300,000 years of climate change. In the past, they apparently were able to adapt both to the changing environment as changes in prey populations. The ice-age grassland, unlike the modern tundra, was a nutrient-rich landscape and able to sustain large herds of herbivores, like mammoths, horses and reindeers. Also, the role modern humans played in the demise of the Neanderthals remains unclear. Some recent archaeological finds suggest that instead of mutual competition, there was an cultural exchange, even of genetic material, between the different human species.