Proximate Cause of Climate Change

Human population growth is a proximate cause of climate change. Charlevoix South Pier Light Station, Charlevoix, Michigan USA [Photo: R. Wottrich]

Richard Wottrich, Atlanta USA


Global warming and climate change are linked to overpopulation.

Developed Economies experience slowing birth rates, leading to less attention given to overpopulation effects.

The earth cannot support its human population today, let alone in 2050, or in 2100.

Air conditioning is on track for huge increases in global energy consumption.


Charlevoix, Michigan USA, is a tiny wealthy enclave of vacationers in Northern Michigan on the shores of Lake Michigan. It is a truism that as populations of humans in Developed Economies become more wealthy their birth rates decline. Charlevoix’s population has dropped from 3,183 in 1990 to 2,529 in 2016 – a decline of 20.5 percent. These are the rose colored glasses that people of means and ‘influencers’ gaze through in Developed Economies when contemplating climate change and its connection to overpopulation.

That global warming and climate change are impacted by humans is a given. Scientists have done the work and the connection is clear. Why then will nobody discuss the proximate cause of climate change – overpopulation? Humans consume and use natural resources to gain consumption opportunities. The more humans we have, the more consumption we have, the more climate change we have. Why is discussing human overpopulation the ‘third rail’ of the climate change discussion? Population growth and climate change are both geometric. The link is unquestionable.

Too Many Humans

There are 7.4 billion humans on earth today. Over two billion humans have nothing. Over 700 million humans are starving to death at any given time. Leaving the politics of the wealth gap and food distribution aside, earth cannot support the humans it has now. The United Nations DESA report has projected 9.7 billion humans in 2050 and 11.2 billion in 2100. Does anyone really believe that climate change can be reversed in the face of another 2.3 billion humans by 2050? Or 3.8 billion by 2100?

Even the relatively wealthy EU added 1.5 million people last year, growing to 511.8 million at the start of 2017. The invidious facts of population growth insure that the countries with the highest standard of living have the lowest birth rates. Meanwhile Africa, with 1.2 billion humans, is projected to grow to 2.5 billion by 2050 and 4 billion by 2100. Asia and Oceania will be at 5.3 billion by 2050 and the Americas will be at 1.2 billion.

Air Conditioning

Consider just one factor in human consumption impacting climate change – air conditioning.

Air conditioning is virtually a ‘right’ in the U.S. and studies have consistently shown that human comfort is key to productivity. Therefore more air conditioning, means greater productivity, means more energy consumption, means rising global temperatures, means more air conditioning. You could look it up.

But what if everyone wants more air conditioning? They do. Nearly all of the world’s biggest cities are in tropical climates. Well over a billion people reside in mega-cities like Guangzhou (44 mm), Shanghai (26 mm), Bogotá (30 mm), Mumbai (20 mm) and on and on.  A modern city-state like Singapore could not exist without air conditioning. Nearly 55 percent of the world’s population lives in urban areas, which is expected to increase to 66 percent by 2050.

Global sales of air conditioners are increasing at an annual growth rate of 18.5 percent – a trend that expected to accelerate; perhaps by an order of magnitude by 2050.  The U.S. uses more energy every year on air conditioning alone than the total energy consumption of Africa and its 1.2 billion people. The climate impact of U.S. air conditioning on rising global temperatures is roughly 500,000,000 metric tons of carbon dioxide per year.

China, the world’s largest energy user and pollution producer, will surpass the U.S. as the world’s biggest user of electricity for air conditioning by 2020. Nearly fifty million air-conditioning units were sold in China in 2016 and total units in China will double in five years.  However while urbanized China, Japan, and South Korea will quickly approach their respective air-conditioning saturation points, the greatest demand will appear in South Asia and especially in India. A report on the global explosion in air conditioning by Lawrence Berkeley National Laboratory projects that the world is poised to install 700 million air conditioners by 2030, and 1.6 billion of them by 2050.

Much of this is logical and intuitive at the same time. But we don’t know what we don’t know – every baby born adds to the geometry of climate change. Over 130 million babies are born every year, netting after human deaths to a gain of over 75 million new mouths to feed every year – year after year. That is another United Kingdom or another Turkey every year.

Until the climate change discussion takes into account the proximate cause of global warming, no realistic progress can be achieved.

Richard Wottrich, CEO and Senior