Bjorn Lomborg's Climate Change Methods & Measures

This article is an excerpt from the Shortform book guide to "False Alarm" by Bjørn Lomborg. Shortform has the world's best summaries and analyses of books you should be reading.

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What’s the best way to measure climate change and its impact? What does temperature have to do with wealth?

According to progressive media and politicians, climate change constitutes an existential threat to humanity, requiring drastic cuts in carbon dioxide emissions to avoid catastrophe. According to Bjorn Lomborg, climate change poses a significant threat, but it’s not cataclysmic.

Keep reading to understand the methods and measures Lomborg uses in his analysis.

Bjorn Lomborg’s Climate Change Assumptions

We’ll discuss the methodological assumptions that Lomborg depends on. These assumptions provide an objective measure for evaluating climate policies.

Temperature: The Proxy for Climate Change

For Bjorn Lomborg, climate change is best understood by looking at temperature. He asserts that temperature is the best proxy for climate change. Admittedly, climate change has numerous effects: It leads to floods, droughts, and rising sea levels. But, these effects are connected to one factor: temperature.

(Shortform note: Although temperature is the main measurement of climate change, scientists use a variety of other measures. For example, they measure average wind speed and direction to evaluate extreme weather events, and they measure precipitation to see further impacts on the climate.)

Lomborg agrees with the scientific consensus that temperatures rise because of CO₂ in the atmosphere. Since CO₂ lets more heat into the atmosphere while blocking its escape, it increases temperature. Further, because fossil fuels—like coal, oil, and gas—emit CO₂ when burned, using them increases global temperatures. Beyond fossil fuels, CO₂ can also enter the atmosphere via natural processes, like forest fires or decaying animals.

(Shortform note: Besides CO₂, other “greenhouse gases” contribute to rising temperatures. These include methane, nitrous oxide, and hydrofluorocarbons. However, CO₂ is responsible for over 80% of the U.S.’s greenhouse gas emissions.)

However, global temperature depends on the atmosphere’s total CO₂ levels. Consequently, Lomborg observes that reducing emissions won’t necessarily reduce global temperature; rather, it will reduce the rate that temperature increases. And, although oceans and forests reduce our annual carbon emissions by about 50% by absorbing CO₂, there’s still increasingly more carbon in the atmosphere each year.

(Shortform note: Because the CO₂ emitted in the past remains in the atmosphere until it’s absorbed by oceans and forests, global warming wouldn’t cease even if we stopped carbon emissions entirely. Even if that were to happen, scientists estimate that global temperature would still rise by 1.1°F by 2060.)

The MAGICC Model

To model the effects of CO₂ on global temperature, Lomborg cites the Model for the Assessment of Greenhouse Gas Induced Climate Change (MAGICC), which United Nations’s (UN) climate scientists rely on. This model evaluates different possible emissions outputs, depending on the steps we take to reduce fossil fuels, to predict increases in temperature by 2100.

Using MAGICC, Lomborg observes that the “middle of the road” scenario—which sees no drastic emissions cuts—results in an increase of 7.4°F by 2100, compared to preindustrial times. So, 7.4°F is the benchmark Lomborg uses to assess proposed climate policies.

(Shortform note: A 2012 report by the World Bank provides more concrete projections of what would happen if the temperature rises by 4°C (7.2°F) by 2100. For example, they claim that the sea level will rise by about one meter, which would put many low-lying regions underwater and make others uninhabitable. Moreover, the increase in CO₂ that the oceans absorb will increase ocean acidification, which will cause many coral reefs to start dissolving. Finally, regions like Amazonia could see a 100% increase in forest fires by 2050 alone.)

Gross Domestic Product: The Proxy for Prosperity

Next, Lomborg asserts that gross domestic product (GDP) is the best proxy for prosperity. In short, GDP measures the total value of goods and services in a given society.

Although GDP doesn’t measure every aspect of prosperity—like health, education, and life satisfaction—it’s highly correlated with those aspects. For example, higher GDP means there’s more money to invest in healthcare or schools. In general, increased GDP means more flourishing citizens.

What GDP Misses: The Value of Human Life

While GDP captures many measures of prosperity, it doesn’t reflect the inherent value of human life itself. Further, because climate change could cause an additional 250,000 deaths per year by 2050, evaluating climate policies solely in terms of GDP could lead us to underestimate the weight of these deaths.

In particular, some have argued that human life is infinitely valuable: There’s no finite value that a human life is worth. Because every human life is equally valuable, they reason that this equality would be an unbelievable coincidence if our value were finite. For example, it’s implausible that every human life is worth some arbitrary sum—say, $4,322,000. Rather, if our lives are equally valuable, it makes sense that they’re infinitely valuable.

If it’s true that human lives are infinitely valuable, climate policy calculations become messier. For instance, suppose a policy would increase global GDP by $500 billion, but cause 500 deaths to rising temperatures. While Lomborg might recommend the policy on the basis of increased GDP, it’s unclear whether any amount of GDP is worth the 500 lives lost.

However, Lomborg observes that GDP and temperature are directly proportional: As GDP rises, countries emit more CO₂ as they move from industries like agriculture to manufacturing, and as their citizens gain wealth they spend more on goods and services, which leads to more emissions. Conversely, many policies that reduce carbon emissions result in lower GDP, since countries have to switch from cheaper energy sources, like fossil fuels, to more expensive alternatives, like solar energy.

(Shortform note: Although increased GDP has a statistically significant correlation with increased carbon emissions, other studies observe that, as per capita income increases in wealthy countries, the rate of increased emissions typically decreases. In other words, the relation between average income and carbon emissions isn’t linear: As income increases, emissions increase to a lower extent.)

So, Lomborg concludes that, when we assess climate policies, we must consider the effects of increasing temperature alongside the effects of increasing GDP.

Bjorn Lomborg’s Climate Change Methods & Measures