The IPCC climate change assessment report on Impacts, Adaptation and Vulnerability, to be released in Japan on March 31, highlights the grave risks we face as the climate changes. But some news coverage previewing the release has focused on the views of Richard Tol, an IPCC author who opted to withdraw from the author team drafting the report summary to seek a larger spotlight for his outlier views.

Earlier March 29 post: Previewing the new IPCC assessment of risks of climate change impacts

The following is a guest post by Climate Nexus (text in PDF format here):

Outlier Scientist Seeks Spotlight as New IPCC Report

Outlines Climate Risks

As hundreds of scientists work to come to consensus on a summary of global climate change impacts and vulnerabilities, an outlier scientist has sought a larger spotlight for his fringe views. The Working Group II (WGII) report of the Intergovernmental Panel on Climate Change (IPCC), to be released in Japan on March 31, highlights the grave risks we face as the climate changes. But some news coverage previewing the release has focused on the views of Dr. Richard Tol, an IPCC author who opted to withdraw from the author team drafting the report summary (known as the Summary for Policymakers) due to what he claimed were the “alarmist” nature of early drafts. This wasn’t a last-minute debate — Tol withdrew last year, although media have only recently shown interest. In fact, the summary is a conservative portrayal of the state of climate science understanding.

  • Tol’s outlier views underscore the IPCC’s role as a consensus document, attempting to bring in as many diverse viewpoints as possible. That includes those such as Tol with connections to climate skeptic groups. Tol may have been dissatisfied with this process, but he had the same opportunity as any scientist.
  • The report ultimately reflects the fact that Tol’s work is outside the mainstream. According to a leaked copy of the current draft, the report finds that the impacts of climate change are and will continue to be negative. It doesn’t “conceal” the benefits of climate change in localized areas, but it makes it clear that the balance of impacts is harmful overall. The report also shows there are limits to the potential for adaptation.
  • The report shows how important it is to begin reducing emissions immediately. We’ve already caused some warming, and there’s more on the way. Our choice now is to reduce emissions and experience the impacts of moderate warming, or delay and experience extreme warming. Voices such as Tol that promote the “benefits” of warming are presenting a false choice.

Impacts of warming are negative, both for agriculture and GDP.

The WG2 draft report is clear that agricultural impacts of climate change are negative (Summary for Policymakers, p.3 line 15). The report doesn’t hide the fact that some areas will experience positive agricultural impacts, but it concludes that negative impacts will outweigh positive impacts on a global scale, now and into the future. A recent literature review backs up this claim, reviewing negative impacts on yield for warming of 2ºC. The report also concludes that crop markets are sensitive to climate extremes, judging by recent spikes in food prices following extreme events in key producer countries (SPM p.3 line 15).

In interviews Tol has dismissed this finding, saying, “They will adapt. Farmers aren’t stupid.” But the report is also clear that adaptation carries costs and limits. For example, as warming approaches 4ºC, even the best adaptations will not be able to avoid serious threats to food security (WG2 SPM p.10 line 19). And this is occurring in a world where global demand for food is expected to increase.

With respect to global GDP, the WG2 report offers cost estimates only up to 2.5ºC of warming. These impacts are negative, estimated to cost up to 2% of global income, which is acknowledged to be only a partial estimate. In fact, the costs of 2.5ºC of warming laid out in WG2 are something of a best-case scenario (or at least a reasonably good scenario), showing what will happen IF we take strong action to reduce carbon emissions. If we do not take action on climate mitigation, we could be experiencing around 4ºC of warming by 2100 according to the business as usual (RCP 8.5) scenario (WGI Annex II Table 7.5). That’s uncharted territory and possible even within the lifetimes of some who are alive today.

Other estimates suggest the high impacts on global GDP with warming of 4ºC (For example the Stern Review found impacts of 5-20% of global GDP). GDP also does not fully account for humanitarian disasters to poorer countries. Extreme impacts in poor, tropical areas (which are expected to be the first to experience the most severe disasters) may not significantly affect global GDP because of the low standard of living – but they still matter. Reports like the World Bank’s Turn Down the Heat portray likely consequences for vulnerable populations.

Discussing benefits of warming presents a false choice.

Furthermore, even Tol acknowledges that warming will be detrimental at high levels, which is where we’re headed without climate mitigation. In fact, we may already be committed to half of the 3ºC of “moderate” warming that Tol believes will be beneficial. This means that our choice is between reducing emissions in order to experience moderate (rather than severe) warming, or doing nothing and experiencing severe warming, beyond 4ºC. As Tol wrote in a 2009 paper: “The climate responds rather slowly to changes in greenhouse gas emissions. The initial warming can no longer be avoided; it should be viewed as a sunk benefit.” Some are spinning Tol’s work to present a false choice between no warming and moderate warming, but this isn’t really an option available to us. Action now is advisable under any plausible climate scenario: the risks are simply too high to wait.

The WGII summary is a consensus product with many voices.

The IPCC included Tol as an author despite his connections to the Global Warming Policy Foundation, which has repeatedly attacked the IPCC, refused to disclose its funding sources, and promoted questionable science. But the report is a consensus document, and if the literature does not support a viewpoint, it won’t be emphasized. As Bob Ward, policy and communications director of the Grantham Research Unit on Climate Change and the Environment at the London School of Economics, told Reuters: “Of the 19 studies he surveyed only one shows net positive benefits from warming. And it’s the one he wrote.” As a coordinating lead author of the underlying chapter on economic impacts, Tol himself ended up detailing the negative net impacts of climate change. Yet, he is contesting a summary of the whole report that is consistent with the findings of his chapter. The real consensus shows that climate change is serious and detrimental, and we need to act now to stop it.