Climate Change Causes

The basic cause of climate change is the production of greenhouse gases – for flights, industry, electricity production and car journeys. But it’s worth reviewing some of the reasons we’re producing so much of these gases.


It’s fairly intuitive that per-capita, rich countries contribute a lot more to climate change than poor ones; those rich countries pump more carbon from sources like power stations, airplanes and cars. What is less obvious is that within a single country there is a very strong correlation between an individual’s income and their personal carbon footprint. “Tell me your income and I will tell you your carbon footprint” says Halina Szejnwald Brown and she shows the same, very clear correlation in two studies, one in the US and the other in China. Kevin Ummel wrote the US Study; on average someone in the top 20% by income pollutes 3 times more than someone in the bottom 20%. 

It’s obviously a simplification, but if someone earns more, they generally spend more; and almost everything you buy has a carbon footprint associated with it. 

Population growth

A simple consequence of having more people on the planet is that they consume more stuff and increase the planet’s carbon footprint; the world’s population has more than trebled in the last 80 years

Growth in the high carbon economy

A disproportionately large percentage of the growth in the world economy has been in carbon intensive sectors. Over the last 40 years, the average adult income in the world has risen 64%; but the number of flights has risen by a factor of 6. In the same period in the UK, the number of cars has risen twice as quickly as the population. 

Developing Countries are developing

Throughout the world, countries are developing and more of their population are consuming like Americans or Europeans. China’s spectacular growth in the last 30 years has fueled its growing carbon footprint. You can see how upward mobility in China at an individual level has contributed to this footprint by looking at meat consumption (increased by a factor of 2.5 in 28 years) or tourism (more than doubled in the last 20 years). 

Countries like Russia, Tunisia, Mexico, Brazil and the Philippines provide a growing class of consumers that rival ‘traditional’ western consumers; for example, in 2018 more than 50% of their adults own a smartphone. 

As a nation, China overtook the US as the biggest emitter of CO2 in 2006 but per capita the USA still emits twice as much CO2 as China. 

Hidden government fossil fuel subsidies

While governments talk green, they often act carbon. In particular, they provide subsidies for fossil fuels and hence encourage climate change.

Pollution is free

Right now, we are all free to emit CO2 into the atmosphere; for example I can decide whether to drive or take the train based on convenience and cost without having to account for the much higher CO2 emissions associated with driving. I’m not charged the social charge of carbon for my emissions; by and large, the same thing goes for enterprises as well. 


55% of the world’s population now lives in cities and that is due to rise to around 68% by the middle of the century. This growth in cities spurs a demand for building and this, in turn, contributes to global warming. 

Cement is commonly used in all forms of building, but it has a massive carbon footprint. As the BBC reports, “If the cement industry were a country, it would be the third largest [greenhouse gas] emitter in the world – behind China and the US. “

In cities everywhere, the standard choice for a prestige building is the glass skyscraper, even in hot climates like the Middle East. As the Guardian reports, it’s a complete folly to build a vertical greenhouse and then install powerful air conditioning to make it liveable. Air conditioning accounts for about 14% of all energy use today; buildings should be designed to minimize its use.

Convenient Choices Are Often Environmentally Poor

Today, it’s usually more convenient to drive than to take public transport; the exception occurs in big cities where parking is a problem and people don’t drive. Likewise, it’s a lot more convenient to go to the supermarket rather than some local market. Everyone is very busy today, especially if they are working with a family, and convenience is very important. 

The Government Pollutes as Well

What is a sustainable value for a personal carbon footprint? In other words, how much carbon can we sustainably produce? There isn’t a single accepted value here, but different sources suggest the target is between 2.0 tonnes of CO2 per person per year to 3.0 tonnes of CO2 per person per year at the current population of the earth. The world average for 2017 was 4.9 tonnes, so – on average – we have to half our carbon footprints. 

But translating that average into targets for each of us gets more difficult. The fairest, simplest strategy would be to say “every country needs to have a personal carbon footprint under 2.5”. Countries already under 2.5 don’t need to do anything – e.g. India at 1.7 (in 2014). Countries above that need to act – e.g. the USA at 16.5, China at 7.5, the UK at 6.2 and France at 4.6 (all 2014 figures). This seems reasonably fair; but it’s only achievable with big government changes as well as personal changes. 

The personal carbon footprint isn’t really personal; it’s the country’s footprint divided by its population; some of the country’s footprint is from personal consumption (driving, flying, heating, food) and some is from providing infrastructure and public services – including police, roads, libraries, the court system and the military. These public services produce CO2 and, because they are available equally to the population, they become part of everyone’s personal carbon footprint. These public services define a floor for everyone’s personal carbon footprint and one study for the US puts this at 8.5 tonnes of CO2 per person per year – even for a homeless person

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