Statistics: The middle tells you nothing about the extremes

When talking of the Syrian conflict this evening, my Lebanese friend said: “Humans are made up of two halves – sometimes you get the top half, made up of heart and head, but too often it’s the lower bit, which is stomach, sex and kicks.” Focusing on the middle tells you nothing about the two extreme halves, each of which can bring about wildly different outcomes warns IIED’s Director Camilla Toulmin.

Occupy London protestors outside St Paul's Cathedral.

In commenting on the middle versus extremes, others have said “Lies, damn lies, and statistics.” Two examples of statistics at their devilish work are provided by climate change, and economic growth. First, the Daily Mail and other pundits who want to belittle the credibility of climate science argue that the latest average global temperatures demonstrate that if climate is changing, it’s doing so very modestly, if at all, and that the models used are hopelessly inadequate. Hence, we should stop trying to shackle economic growth by imposing controls on carbon emissions, and get rid of subsidies on renewable energy.

The second case examines and questions our measures for economic growth and prosperity. For too long we have relied on taking the average GDP per person as a good proxy for a nation’s well-being and, while acknowledging the importance of distribution, this has usually been relegated to esoteric discussions of Gini coefficients (used to measure the inequality of income levels).

On climate change, it is puzzling that the overall global temperature has been flat-lining for the last decade. Climate scientists offer various reasons for why this might be so, such as the high level of aerosols in the atmosphere, and low levels of solar activity which both depress warming. Equally, the last few years have seen greater influence from the La Niña currents in the Pacific which bring lower temperatures. Yet, basic physics tells us that burning all the fossil fuel energy we do must generate a consequence. It looks increasingly likely that heat and energy from carbon emissions are being captured in the oceans, and taken down to lower levels where they are not so visible to measurement devices. But we should also remember that the planet Earth is a complex multi-layered system, and our models can only imperfectly describe how these layers of atmosphere, land and oceans interact.

Averages, however, tell only a small part of the picture today. Climate change has been affecting different parts of the planet in a very uneven fashion, and this looks likely to continue. In the short term, much of the northern hemisphere may actually gain from longer growing seasons, warmer winters and carbon fertilisation of crops. This may partly account for the stubbornness of countries like Canada to take any measures to curb greenhouse gases. By contrast, in many parts of the southern hemisphere, climate change has already brought much harsher more difficult conditions. In the western African Sahel region, rainfall has fallen by 30% over the last 40 years, stressing farm and livestock systems that were already short of water. In the Horn of Africa, the fluctuations of drought and flood have been rendered yet more volatile. In Bangladesh, sea level rises and more intense storm surges have forced hundreds of thousands to leave their homes and land. If these extremes become more common, looking at the average doesn’t give the full picture and hides a very different, volatile reality for those living in the tropics.

Similarly, if measuring economic well-being through a simple analysis of GDP, the US is often portrayed as the most successful economy on earth, with lessons to offer others. But this hides the extreme inequality to be found within its borders. The October 13th issue of the Economist has brought to the fore evidence of the extraordinary skew in disposable incomes that has developed over the last 20-30 years in the country. They show that, including capital gains, the share of national incomes going to the top 1% of Americans has doubled since 1980 (from 10% - 20%) to where it was roughly 100 years ago. Meanwhile, the top 0.1% of Americans (representing just 16,000 families) have quadrupled their share of the national income, from 1% to almost 5% — “a bigger slice of the pie” than the super-rich received even 100 years ago.  

While global inequality is decreasing, inequality within most countries – such as India, China, South Africa, Canada and Britain – is rising. The main exceptions can be found in Latin America, where countries like Brazil and Chile are bucking this trend.

In Britain and North America there are many reasons which help explain this big shift in distribution over this period, from the rise in the financial sector, the fall in education amongst lower income groups, cutbacks in the regulation of corporations, and the impacts of globalisation which have reduced wage rates and union bargaining power in richer nations.

Averages like a country’s overall GDP mask these extremes of inequality. As Chrystia Freeland argues in her New York Times opinion piece, inequality becomes a big problem for society as a whole when those at the top use the political system to perpetuate their control, and shut the door on innovation and creativity bubbling up from below. While the super-rich often vaunt the importance of free markets and the private sector,  it is usually through acquiring preferential influence over government that they can further advance their interests and wealth; they “channel the state’s scarce resources in their own direction”, and stop others feeding at the trough.

Anyone who cares about addressing climate change should care about restoring democratic process, and seek accountability to the average Joe. We need to find a means to break the grip of the 1% (and the 0.1%) on the political levers of power. If we don’t, we’ll see ever more extreme events – with the rich getting ever richer and the climate system delivering harder, harsher conditions to those who’ve contributed least to global warming.

Humans have been endowed with remarkable intelligence, yet we’re often lazy of mind. An average gives you singular clarity, but can be misleading.  Just as both torso and abdomen are equal parts of the human being, looking at the spread of data that lies behind a single figure can lead to seeing a more complex, full picture in the end – warts and all.

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