Contrary to alarming suggestions by Bjørn Lomborg in his article for Foreign Policy, DARA's recent Climate Vulnerability Monitor report is not a house of cards hinging on "one change in the model, namely including the impact from heat on labor productivity." Our report is a comprehensively updated assessment of the harm to human society and current economic development if we fail to act on climate change. It is anchored in latest mainly peer-reviewed studies and was developed in conjunction with detailed field research in Africa and Asia as well as successive review phases by more than 50 leading experts.
Lomborg asserts that the solutions the report promotes will be costly, but the whole point is to look at climate change through the lens of minimizing losses and maximizing gains in human, economic and environmental terms. As its title -- "A Guide to the Cold Calculus of a Hot Planet" -- suggests, the report is actually cold-minded good news, not "unfounded alarmism and panic." The costs of action may be "huge," but so are the benefits: We can deal with climate change, save millions of human lives, help slow rapid environmental degradation, rescue lagging progress on poverty reduction, and actually make money in the process.
The main difference between our study and earlier research comes from a revised treatment of the consequences of climate change versus its causes. The distinction helps to explain what is wrong with Lomborg's questioning of our estimations of costs and deaths due to climate change.
Most previous research of this kind has considered the impacts of climate change together with an effect called "carbon fertilization," meaning the stimulus of plant growth due to high atmospheric concentrations of carbon dioxide. CO2 is a natural ingredient in plant photosynthesis, and as its levels rise many scientists expect crop yields to improve in certain places.
The thing is, what we call "the climate" only means average weather. Climate change is simply a change in average weather. Crucially, atmospheric CO2 and carbon fertilization are not consequences or impacts of shifts in the weather. They relate instead to the causes of climate change. Failing to tackle climate change will lead to both temperature and CO2 rising in tandem. So it makes perfect sense to account for carbon fertilization when considering the future impacts of climate change, even when it is not one. In fact, on the basis of current research, we estimated that by 2030, carbon fertilization could be generating hundreds of billions of dollars in benefits every single year. For these reasons, prominent experts rightly consider carbon fertilization entirely relevant for the global warming debate.
But we make the case that many other effects that are similarly tied to the causes of climate change (but not weather-related) are of equal relevance to the global warming debate and have traditionally been overlooked.
Take the world's oceans for instance, which absorb one third of all CO2 released. Doing so makes them more acidic and harms marine life -- especially coral, molluscs, and shellfish that struggle to access key nutrients as water pH changes. This is not a weather-related impact, but it is an important cost to the fisheries sector. Another example worth considering is rising levels of ozone in smog at ground level that. Unlike CO2, smog is toxic for plant growth and triggers further losses.
Our simple suggestion is that either you take all relevant impacts tied to the causes of climate change into account, or you take none of them. Our report separates out both issues to enable independent examination. Is this deliberately misleading, as Lomborg suggests? No, it is clarification: Considering only carbon fertilization without other non-weather effects only distorts the true costs of climate change. It is one of the key reasons why many experts have concluded that overall climate change may not be much of a cost to the world economy in the decades ahead and it is a central pillar of the economic arguments for taking less action to address the problem, such as those espoused by Lomborg.