Next to the oxygen in the atmosphere, climate is the most important factor in human life because climate determines food availability, clean water and favourable temperatures upon which all healthy bio-systems depend. It determines the proportion of the planet which will support human life.

It hasn't always been this way

Humans have lived on earth for hundreds of thousands of years, but it is only in the past 10,000 years that we have become sophisticated enough to become a progressively creative species. Human civilization was not created by an improvement of our physiology, it has been the result of slowly accumulating knowledge.



A relatively stable climate allowed our ancestors to develop agriculture and towns to grow. The result has been higher forms of learning and more elaborate social structures.

The graph below shows the exceptional stability of the climate we have enjoyed in the past 10,000 years compared to the previous 90,000 years. Human history has largely been written in this period of relative stability but even then small changes in climate have laid waste to numerous civilizations.

Compare the magnitude of the fluctuations in the Holocene to the previous periods and imagine the severity of conditions faced by early humans. Those gross climate fluctuations would have meant far less food availability, short life spans and much more frequent nomadic wandering to seek necessities. Under these conditions, it would have been almost impossible to accumulate material goods, tools or any higher level of learning necessary to allow a continuous surge of social and technical development.

Just how difficult would life have been?

Compare the tools humans used 2 1/2 million years ago to the state-of-the-art Clovis points of 12,000 years ago. These tool changes illustrate a very large advance, but it took humans 2 million years to progress from crude chipped stone to finely crafted spear points.

From those spear points, 2 million years in the making, it only took us 10,000 years to put a human on the moon. That technological leap off the planet was made in 1/200th of the time it took to progress from broken stone to crafted stone.

Climate change is heading in the wrong direction

Climate determines the health and richness of the environmental systems humans depend on. It determines how much of our time will be devoted to producing food and, consequently, how much time we will have left to improve our learning, our society, our technology and our infrastructure.

The warming of the planet is underway, and it is likely to approach the scale of the changes our ancestors experienced over the previous hundreds of thousands of years ago. This degree of climate change will present immense challenges for human society.