Global warming explained to the man on the Clapham omnibus*

Post with image

Studies and analysis of samples taken from the core of polar ice layers show that over the last 800,000 years, the level of concentration of atmospheric CO2 has ranged between highs of about 300 parts per million (ppm) and lows of about 170 ppm! Those highs were reached on several occasions – 130,000 thousand years ago, 240,000 years ago and 330,000 years ago. However, it appears that things have now changed taking us out of the historic range: in 2008, the concentration of atmospheric CO2 was about 375 ppm, significantly higher than the previous highs.

Man’s fingerprint

Naturally, the Earth annually emits 190 GtC (giga tonnes of carbon). These 190 GtC are equally naturally reabsorbed by the Earth in adherence with a harmonious balance that has prevailed over time. However, human activity has come to disturb this equilibrium. While it involves the emission of what seems to be a relatively modest 8 GtC per year (measured by average emissions over the period 1990-1999), of which 4.8 GtC are reabsorbed by the Earth, it leaves 3.2 GtC in the atmosphere.

This relatively small addition, in proportion to the total mass of carbon, has potentially momentous consequences. The increase in emissions can be seen as adding, each year, an extra layer (albeit thin) to those already accumulated in previous years (and remember, as Einstein said, “The most powerful force in the universe is compound interest”). Compounding means the seemly innocuous extra layer each year acquires another dimension when measured over a period of 60-70 years (i.e. from 1950 to today).

Higher emissions and temperatures: it’s a straight line

Moreover, it turns out that the global warming observed between 1870 and today is a linear function of the cumulative amounts of greenhouse gases emitted in the interim period. Between 1870 and 2011, humans emitted 513 GtC corresponding to an increase in temperature of about 0.9 °C; the total mass that would trigger the fateful increase of 2 °C, corresponds, in the view of IPCC scientists to 783 GtC. This, in their opinion, is the critical threshold beyond which the phenomena of climate change may lead to disasters; so, there would seem to be scope for further emissions of just 270 GtC.

But in 2011, carbon emissions were 10.3 GtC (compared to 8 GtC each year between 1990 and 1999, just 20 years ago cf. sopra). If we accept the unlikely supposition that emissions will remain at this level in the future, then on the basis of the above-mentioned data we will have to stop emissions of greenhouse gases after just 26 years (270 divided by 10.3). And, 26 years… that’s practically tomorrow! So it’s urgent to take action since it’s three minutes to midnight. The implications are that investments should be immediate, sustained, massive and widespread.

A global warning on global warming

According to Intergovernmental Panel on Climate Change (IPCC) experts, even with a temperature increase of only 2°C, greenhouse gas emissions from human activity will have consequences that are difficult to predict, both in terms of their scale and in location, for the level of the sea, patterns of rainfall, ocean acidification or soil productivity. Numerous coastal regions will likely be submerged, production of crops be subject to massive change and entire populations be forced to seek a livelihood elsewhere.

A sign of things to come?

We must act to avoid the immeasurable disasters that global warming could cause. The drought currently affecting California is perhaps the precursor of weather events more dramatic than anything we have experienced hitherto. And even were these alarming predictions ultimately prove to be false and incongruous as numerous climate skeptics suggest, can humanity take the risk of underestimating it?

For those investors who would think that these issues are too important to ignore, there are solutions to help control emissions of greenhouse gases. Investment funds exist that invest exclusively in those companies that contribute to a better use of energy or to a recycling of waste.


* The man on the Clapham omnibus is a reasonably educated and intelligent (but nondescript) person. The term is used in English law. In Australia, the expression has inspired the New South Wales and Victorian equivalents, “the man on the Bondi tram” (Sydney) and “the man on the Bourke Street tram” (Melbourne,). In Hong Kong, the equivalent expression is “the man on the Shaukiwan Tram“. Sometimes referred to as the Kansas City milkman, Joe Bloggs or the man in the street. More on and on


Alexandre Jeanblanc

Investment Specialist, SRI

Leave a reply

Your email adress will not be published. Required fields are marked*