HH Lamb & The Early Holocene

By Paul Homewood

Continuing my review of Hubert Lamb’s “Climate, History and the Modern World”, originally published in 1982, let’s take a look at what he had to say about the early holocene, between the end of the ice age and around 1000 BC.

He points out how the Sahara was a much wetter place than today, and how this began to change around 3000 BC, coinciding with the time of the Piora Oscillation, when glaciers began advancing in the Alps and elsewhere.

In Chapter 7, he goes into more detail.

Studies of the upper limit of trees on mountains can give a good approximation of temperatures through time. Studies by Vera Markgraf indicate that the tree limit was at its highest around 5000 BC. Since then, it has lowered, indicating a summer time temperature drop of 2C to 3C. The rebound during the MWP is also unambiguous.

This warm period is known as the “Atlantic Climatic Period”, and Lamb offers other evidence.

Lamb also touches on the question of sea level, suggesting that sea level was likely at its highest around 2000 BC, when “ it may have stood a metre or two higher than today” (page 116).

He wonders whether a higher sea level may have facilitated the original building of the Suez Canal in 2000 BC.

During these warmer times, not only the Sahara, but other regions of Africa, such as Chad and East Africa, were much wetter than now.

And not only Africa. Further afield, India and China enjoyed a much wetter climate.

Lamb was clear about the causes of this wetter climate. Quite simply, during a warmer climate, all of the weather systems move towards the poles, pushing the anticyclone zone and North Atlantic storm zones north. As a result, the equatorial and monsoon rains penetrate much further north.

After 3500 BC the Piors Oscillation introduced a cooler climate, though perhaps for no longer than 400 yrs.

As mentioned, India also experienced a much wetter climate.

Lamb also looks at research in China, which also finds much higher temperatures than now.

We can finish by looking at the evidence from Britain.

To conclude, Lamb finds clear evidence that the climate for most of this period was much warmer than today’s. He also shows how this led to a much wetter climate across many of today’s arid zones, while at the same time bringing a drier and more settled climate to temperate zones.

All of this makes two things clear:

1) There is nothing “unusual” about today’s climate.

2) The common claim that global warming will lead to more severe droughts in Africa and elsewhere is not supported by the historical evidence.