Media failure on Iraq War repeated in climate change coverage

Stephen Lewandowsky in Skeptical Science: "Iraq is developing a long-range ballistic missile system that could carry weapons of mass destruction up to 700 miles." Iraq is progressing towards "dirty bombs that spew radioactivity, mobile bio-weapons facilities, and a new long-range ballistic missile." An Iraqi defector "tells of work on at least 20 hidden weapons sites...

Those claims appeared in mainstream newspapers during the lead-up to the invasion of Iraq in 2003. All those claims were false. ... A decade later, those media failures are relevant not only because of the war's six-figure death toll and because the Iraqi per capita GDP has so far failed to return to prewar levels, but also because they remind us that the media, including highly reputable newspapers, can sometimes get things quite wrong.

A similar media failure is arguably under way this very moment with regard to climate change. The most recent report of the Intergovernmental Panel on Climate Change (IPCC) concluded with near certainty that human economic activity is responsible for ongoing global warming, and some of the largest insurance companies on the planet have blamed the increase in losses from extreme weather events to climate-related disasters.

...One notable difference between pre-invasion reporting on Iraqi WMD and climate change is that, in contrast to the near-hegemony of war-supporting reporting (at least in the U.S.), the public has a broader choice now when it comes to climate change: While there is a large supply of disinformation that threatens the public's right to being adequately informed, there is also no shortage of actual scientific information, both in the mainstream media and beyond.

The diversity of sources empowers the public to select their information wisely, but it also provides a playing field for the dominant influence of people's cultural worldviews or "ideology", which can override even education. People whose core personal values are threatened by possible responses to climate change, such as a price on carbon or regulatory measures, are known to rely on media sources that are more likely to create confusion about climate change than disseminate scientifically accurate information....

Orwell plaque shot by Simon Harriyott, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license

How will crops fare under climate change? Depends on how you ask

Morgan Kelly in Princeton Journal Watch: The damage scientists expect climate change to do to crop yields can differ greatly depending on which type of model was used to make those projections, according to research based at Princeton University. The problem is that the most dire scenarios can loom large in the minds of the public and policymakers, yet neither audience is usually aware of how the model itself influenced the outcome, the researchers said.

The report in the journal Global Change Biology is one of the first to compare the agricultural projections generated by empirical models — which rely largely on field observations — to those by mechanistic models, which draw on an understanding of how crop growth and development are affected by the environment. Building on similar studies from ecology, the researchers found yet more evidence that empirical models may show greater losses as a result of climate change, while mechanistic models may be overly optimistic.

The researchers ran an empirical and a mechanistic model to see how maize and wheat crops in South Africa — the world’s ninth largest maize producer, and sub-Saharan Africa’s second largest source of wheat — would fare under climate change in the years 2046 to 2065. Under the hotter, wetter conditions projected by the climate scenarios they used, the empirical model estimated that maize production could drop by 3.6 percent, while wheat output could increase by 6.2 percent. Meanwhile, the mechanistic model calculated that maize and wheat yields might go up by 6.5 and 15.2 percent, respectively.

In addition, the empirical model estimated that suitable land for growing wheat would drop by 10 percent, while the mechanistic model found that it would expand by 9 percent. The empirical model projected a 48 percent expansion in wheat-growing areas, but the mechanistic reported only 20 percent growth. In regions where the two models overlapped, the empirical model showed declining yields while the mechanistic model showed increases. These wheat models were less accurate, but still indicative of the vastly different estimates empirical and mechanistic can produce, the researchers wrote.

…“A yield projection based only on empirical models is likely to show larger yield losses than one made only with mechanistic models. Neither should be considered more right or wrong, but people should be aware of these differences,” Estes said. “People who are interested in climate-change science should be aware of all the sources of uncertainty inherent in projections, and should be aware that scenarios based on a single model — or single class of models — are not accounting for one of the major sources of uncertainty.”…

A corn field, shot by Angela Marie, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license