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The potential impacts of climate change on crop productivity are of widespread interest to those concerned with addressing climate change and improving global food security. Two common approaches to assess these impacts are process-based simulation models, which attempt to represent key dynamic processes affecting crop yields, and statistical models, which estimate functional relationships between historical observations of weather and yields. Examples of both approaches are increasingly found in the scientific literature, although often published in different disciplinary journals. Here we compare published sensitivities to changes in temperature, precipitation, carbon dioxide (CO2), and ozone from each approach for the subset of crops, locations, and climate scenarios for which both have been applied. Despite a common perception that statistical models are more pessimistic, we find no systematic differences between the predicted sensitivities to warming from process-based and statistical models up to +2 °C, with limited evidence at higher levels of warming. For precipitation, there are many reasons why estimates could be expected to differ, but few estimates exist to develop robust comparisons, and precipitation changes are rarely the dominant factor for predicting impacts given the prominent role of temperature, CO2, and ozone changes. A common difference between process-based and statistical studies is that the former tend to include the effects of CO2 increases that accompany warming, whereas statistical models typically do not. Major needs moving forward include incorporating CO2 effects into statistical studies, improving both approaches' treatment of ozone, and increasing the use of both methods within the same study. At the same time, those who fund or use crop model projections should understand that in the short-term, both approaches when done well are likely to provide similar estimates of warming impacts, with statistical models generally requiring fewer resources to produce robust estimates, especially when applied to crops beyond the major grains.

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Environmental Research Letters
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David Lobell
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"The president-elect could enhance confidence in his presidency by endorsing the call of Senators McCain, Graham, Schumer, and Reed for a bipartisan select committee of Congress to undertake a 'comprehensive investigation of Russian interference' and develop 'comprehensive recommendations and, as necessary, new legislation to modernize our nation’s laws, governmental organization, and related practices to meet this challenge'” writes Larry Diamond, Senior Fellow at the Freeman Spogli Institute for International Studies in his latest article in The Atlantic. Read it here. 

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Larry Diamond, Senior Fellow at the Freeman Spogli Institute for International Studies, touched base on why democracy is important, revisited events in Iraq, spoke about Russia and other issues in the Q&A with Jay Nordlinger. Listen to the podcast here. 

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With the future of U.S. health care in flux, questions abound about the incoming Republican administration's impact on federal programs like Medicare and Medicaid. Stanford University scholars Kate Bundorf and Jay Bhattacharya outline possible changes to these programs and their effects on health care for the elderly and the poor.

Kate Bundorf is the chief of the Division of Health Research and an associate professor of health research and policy. Her research focuses on health insurance markets, often including Medicare.

Jay Bhattacharya is a professor of medicine and, by courtesy, of economics. He studies Medicare's financial future -- and it's effect on physician's practices and patient outcomes -- and is currently assisting in the roll-out of MACRA, a new payment reform system for Medicare.

Medicare Post-election by Stanford Health Policy on Exposure

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"Since the end of World War II, the most crucial underpinning of freedom in the world has been the vigor of the advanced liberal democracies and the alliances that bound them together. Through the Cold War, the key multilateral anchors were NATO, the expanding European Union, and the U.S.-Japan security alliance. With the end of the Cold War and the expansion of NATO and the EU to virtually all of Central and Eastern Europe, liberal democracy seemed ascendant and secure as never before in history. Under the shrewd and relentless assault of a resurgent Russian authoritarian state, all of this has come under strain with a speed and scope that few in the West have fully comprehended, and that puts the future of liberal democracy in the world squarely where Vladimir Putin wants it: in doubt and on the defensive" writes Larry Diamond, Senior Fellow at the Freeman Spogli Institute for International Studies, for The Atlantic. Read the whole article here.

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"In Silicon Valley, where I live, the word “disruption” has an overwhelmingly positive valence: Thousands of smart, young people arrive here every year hoping to disrupt established ways of doing business — and become very rich in the process. For almost everyone else, however, disruption is a bad thing," writes CDDRL Mosbacher Director, Francis Fukuyama for New York Times. Read the article here.

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Mosbacher Director Francis Fukuyama describes for The American Interest  podcast this election as a watershed moment for our country, saying that Trump marks a break from the postwar consensus both in economic and foreign policy terms. He also looks at how these latest election results were informed by the political decay he described in his most recent book, Political Order and Political Decay: From the Industrial Revolution to the Globalization of Democracy, before discussing what he sees as an ongoing—and global—backlash against globalization. Listen here.

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Robert MacCoun, a professor of law and a senior fellow at the Freeman Spogli Institute for International Studies, relays the potential risks and benefits of legalizing marijuana. His research focuses on drug policy, and he has written extensively about the effects of marijuana from a legal and health perspective.

California, Massachusetts and Nevada all legalized marijuana in the last election. Does this mean the legalization movement has reached a tipping point?  

If Hillary Clinton had won the election, it would probably feel that way, not because she’s a legalization advocate, but because she’d have bigger fish to fry and would probably continue President Obama’s laissez-faire approach. With the Trump administration’s new cabinet, all bets are off. Still, one in five Americans now live in a state where recreational use of marijuana is legal, and that’s a big market. And as the market grows, the industry’s lobbying clout grows.

What are the health risks post-legalization?

That depends on how much consumption levels increase. There are good reasons to expect marijuana prices to fall, which will increase consumption. Because many people use marijuana without health consequences, I worry less about an increase in the number of people using marijuana than about an increase in the number who use it one or more times daily. There is growing evidence that heavy marijuana use is associated with an increased risk of psychosis. We don’t know if it is a true cause-and-effect relationship; let’s hope it is not. But I think the biggest health threat is dependence, which for marijuana is something like getting stuck in the La Brea tar pits — your world just gets smaller and smaller as you get more dysfunctional.

maccoun stanford9 20 14 727 head shot Robert MacCoun, PhD

How can legalizing states combat these risks?

The good news is that legalization makes possible all sorts of regulatory options that weren’t available under prohibition. States should insist that no marijuana products are to be packaged in a way that entices children. Doses should be standardized, and there should be accurate labeling about the THC content. States should discourage products with high levels of THC, and perhaps encourage products with higher levels of cannabidiol (CBD), an ingredient that seems to counteract some of the harmful effects of THC.

The bad news is that the state ballot initiatives didn’t do much more than give lip service to public health and safety, and industry entrepreneurs are pushing back hard against state regulators. I think the industry is being foolish here — they’ve won eight states but still have 42 states to go. I don’t think they realize how quickly a backlash could emerge if those eight states show rising rates of various adverse outcomes.

Could there be any positive health effects of marijuana use?

Absolutely. There are plenty of lines of evidence suggesting medical benefits for some patients. Intriguingly, several new studies suggest that medical marijuana states may be experiencing reduced levels of opioid use and opioid overdoses. The Catch 22 is that the DEA decided not to reschedule marijuana because there isn’t enough rigorous evidence, but there isn’t enough rigorous evidence because the Feds have made such studies almost impossible to conduct.

Some of the biggest health benefits of marijuana will occur if it turns out that marijuana use is a substitute for binge drinking. There are both physiological and economic reasons to think that might be the case, but while some studies show substitution, others show complementarity. For a researcher, one big benefit of legalization is that it is going to help us finally answer a lot of these research questions.

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