Science Mag’s ‘Once and Future Climate Change’ Coverage

The same week that NOAA’s National Climatic Data Center releases a report confirming that “worldwide, 2012 was among the 10 warmest years on record,” Science magazine devotes a special section to “Once and Future Climate Change.”

The introduction to the magazine’s special section sets the stage for the type of coverage that appears there. The opening reads:

“Anthropogenic climate change is now a part of our reality. Even the most optimistic estimates of the effects of contemporary fossil fuel use suggest that mean global temperature will rise by a minimum of 2°C before the end of this century and that CO2 emissions will affect climate for tens of thousands of years.”

In other words, “Is the climate changing?” is not the big climate question one of the world’s most respected scientific journals is seeking to address. We can take that as given.

Instead, the question they attempt to address in this special issue and, by the way, the one the scientific community has really not yet answered is: What does climate change mean for us, for our ecosystems, for the globe?

The introduction sets the table for the articles that follow like so:

“A key goal of current research is to predict how these changes will affect global ecosystems and the human population that depends on them. This special section of Science focuses on the current state of knowledge about the effects of climate change on natural systems, with particular emphasis on how knowledge of the past is helping us to understand potential biological impacts and improve predictive power.”

More detailed questions (along with some answers, as well as we can currently identify them) follow in the four news stories and seven scientific reviews that make up the special section. The topics covered range far and wide, from the fate of marshes in a world with rising sea levels to the future of species and whether we can expect widespread extinctions from climate change to how humans have evolved in a world with constantly changing climatic conditions to whether climate change will lead to greater threats from infectious diseases.

Flying Blind

They are all interesting papers, but if you’re looking for sound bites and simple answers, you’ll be frustrated. What this coverage makes crystal clear is that we actually know very little about what will happen as the climate continues to warm.

Will we be more prone to infectious diseases as a result of climate change? Maybe from some diseases, but maybe not. Will marshes be threatened by sea level rise? Certainly, but through a combination of human interventions and natural adaptations, many may survive. Will species extinctions become widespread? Hard to say.

It’s a brand new experiment, letting the climate heat up, and we are basically flying blind. We have some insights from what has happened during past climate changes. And we can try to extrapolate from current trends and observations. But in the end it’s mostly conjecture and speculation.

The take-home messages from these papers is two-fold: 1) scientists can ask a lot more questions than they can answer when it comes to impacts from climate change, and 2) a lot more research is needed if we hope to have better answers anytime soon.

So whether you’re a policy maker, a homemaker or a business person trying to figure out how to adapt to climate change, the bad news is there’s not a whole heck of a lot to go on to prepare. That’s one of the reasons when we talk about adapting to climate change we talk about building in resiliency — we need a system that can withstand change in the broadest sense as opposed to one that can deal with a specific outcome or threat. Not a great situation to be in.

A Look at Food Issues

One of the critical topics covered in the special issue of Science is global food security. And that’s the subject I want to take some time here to sum up.

Tim Wheeler of the University of Reading’s Walker Institute for Climate System Research and Joachim von Braun of the UK’s Department for International Development pose a pretty straightforward and also quite overwhelming question: With an estimated two billion people classified as being “food insecure” and the global population expected to grow by another two billion or so by mid-century, how will climate change, with rising temperatures and disruptions in rainfall patterns, among other things, affect our ability to not lose ground on global malnutrition and food insecurity, let alone alleviate them?

The typical approach to answering that question has been to consider food availability; that is, use coupled climate/crop yield models to predict how crop production around the world will respond to changing climatic conditions. (See here, for example.) In general, the results of those model calculations (with the caveat that they are after all just model calculations and not reality) are that crop production will decline, especially in economically depressed regions of Africa and South America where malnutrition and food insecurity are already rife.

But Wheeler and von Braun point out that such a direct-effect-of-climate-on-crops approach only addresses one of the four basic legs of food security. The other three legs — namely, how climate change will affect access to food, utilization of food to form a healthy and nutritious diet, and the presence of  a stable food system — are relative unknowns, even though each one could prove to be more critical to providing food security to large numbers of people in the world than food production.

So let’s take a look at each of these three other legs.

Issues Surrounding Food Access

Climate change will not directly affect access to food but it can “through indirect, but well-known, pathways,” the authors write. They continue: “Access to food is largely a matter of household and individual-level income and of capabilities and rights.” A key part of assessing this coupling is to know how communities and households react to climate shocks.

Another issue is how communities will adjust if climate change alters the geography of where staple crops are produced, especially if local crops are affected. Little is known of these issues although scientists have begun to develop analytical models to begin to learn about them.

The Nexus Between Climate Change and Food Utilization

Food utilization is all about using food to provide people with nutritional well-being and that in turn “depends upon water and sanitation and will be affected by any impact of climate change on the health environment.”

If recent events of widespread floods and droughts are any indication of what the world has in store (see herehere and here), it suggests that climate change, especially if it brings more extreme weather, will greatly challenge people’s health. Witness for example the strong association between outbreak of diseases and floods. And it’s not just a developing world phenomenon; there were plenty of health impacts from contaminated water in New Orleans following Hurricane Katrina.

A complicating factor, and a fascinating one when you think about it, is that so much of the world is going through a “nutrition transition” in lifestyle that leads to “excess caloric intake, poor-quality diets, and low physical activity” that in turn may be contributing to a rapid rise in obesity and chronic diseases such as diabetes. (Yesterday’s good and welcome news that the Centers for Disease Control found that “obesity rate among preschool-age children from poor families fell in 19 states and United States territories between 2008 and 2011” notwithstanding.) The authors note that there is an especially large dearth of research “on the potentially reinforcing effects of these [two] phenomena.” (It’s not obvious to me why these have to be reinforcing effects.)

In Pursuit of a Stable Food System

Climate could be a major kicker in pursuing a stable food system — as its stability depends upon predictability both in crop yields and in price futures. And we have seen how severe weather events like the 2012 drought in U.S. Midwest can affect supplies and prices. Wheeler and von Braun note that in recent years “the world food equation has been at a precariously low level and, consequently, even small shocks on the supply or demand side of the equation will have large impacts on prices, as experienced in 2008.” (See here, here, here and here.) And the poor with limited income will be most vulnerable to these shocks.

Parting Thoughts

So how will folks react to Science magazine’s special section on climate? Well, I suppose if you’re a policy maker, you’re getting some bad news. Not that you didn’t know it already. Climate change is a problem that is not going to go away. And despite all the uncertainties, you’re going to have get busy formulating solutions to address this problem.

If you’re a scientist, like me, you’re not likely to find this material especially uplifting, it’s maybe even a little depressing — there’s so much we don’t know. But one thing we know for sure — there are some really complicated and important questions out there. Keep on keeping on.

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