What can nitrogen do for you?

I got a meeting with the Bobs.

– Office Space (1999)

Ahhh, the meeting.  A centerpiece of professional life that more often provokes adjectives like “dreaded” or “useless”  (or ones far more, um, colorful…) than anything inspiring.  Field scientists can be especially meeting-averse — some I know might sleep in a room full of spitting cobras if it got them out of some university committee meetings.

But not all meetings make you want to swallow a scorpion.   In science, some are a great chance to catch up on the latest goings-on, either in formal talks or over a beer or two, and some are just plain fun as well as catalysts of scientific progress. Such was the case this week.  For the last 4 days, ~ 40 nitrogen junkies of one stripe or another — ecologists, biogeochemists, atmospheric scientists, agricultural scientists, epidemiologists — gathered at the USGS Powell Center in Fort Collins CO to explore how human disruptions to the nitrogen cycle and climate system interact, and what that might mean for key socioeconomic sectors in the U.S.

This was the launch to an effort that Eric Davidson and I are leading, but that is built on the energy, creativity and effort of a long list of scientists around the world.  And it was the kind of meeting I like best.  We brainstormed.  We argued.  We pondered.  We dug for new information; we tossed around ideas both wacky and compelling; we created, refined, abandoned and exhumed one conceptual model after another.  And we walked out the door set forth on some new paths, ones that should not only help us understand the science of nitrogen-climate interactions better, but that might also make a difference in figuring out what society should do about them.

Why nitrogen-by-climate?  Let me do the annoying “answer a question with a question” thing.  Do you like clean water?  Clean air?  A diversity and abundance of food?  A world that’s not tossing species into the dustbin of history? Climate change poses threats to all of those things.  And as it turns out, so too does humanity’s runaway tendency to create, mobilize and spread around vast quantities of the essential element nitrogen (and phosphorus, but I’ll save that for another day…).   Global change scientists sometimes refer to these types of issues as “multiple stressors.”   Kind of like: “Dammit, that key report is due at work tomorrow, my kid is vomiting all over the house, my dog just ate the neighbor’s cat, and the f%$#ing sprinkler valve ruptured and is flooding the basement.”  Not exactly an enjoyable – or sustainable – situation for the recipient of such stresses.

So it goes with the environment and the benefits it provides for our daily lives.  Take the biological diversity of the ecosystems that surround us.   Change the climate, and species can literally start feeling the heat, sometimes blinking out of existence entirely.  Same goes for loading those ecosystems with too much nitrogen.  It can be like flooding a poor but stable town with piles of money – there will be some winners, but plenty of losers and a whole bunch of new chaos.

So what happens when we simultaneously change the climate and load up these ecosystems with nutrients that are typically in short supply?  They’re suddenly dealing with the vomiting kid and ruptured valve at the same time, and the odds of bad outcomes can skyrocket.

In the climate change world, there’s a long list of these worries, and as we all know by now, a societal reluctance to get serious about avoiding (or adapting to) them.  But for some things on the list, maybe that apparent multiple stressor is also an opportunity. Consider air pollution, ozone specifically.  Ozone sucks:  it makes people sick, and in some cases, hastens their demise.  It also slows the growth of our major crops, to the tune of billions of dollars of lost productivity every  year.  Anybody who lives in a city with ozone  alerts knows they happen in summer. Why? Because it takes hot temperatures to fuel the kinds of atmospheric chemical reactions that lead to ozone formation.

But guess what happens if you have Sahara-hot temperatures but not many nitrogen oxide gas molecules in the air?  Well, you sweat like a pig…but you don’t breath in much, if any, ozone.  And that’s because nitrogen oxides are a key control on making that ozone….and getting those high nitrogen oxide concentrations comes from humans messing with the nitrogen cycle.

Same goes for dead zones.  Turns out climate change might often (though not always) make these oxygen-deprived areas of our coastal oceans worse.  But if we don’t dump a bunch of nitrogen and phosphorus into our rivers and then into our oceans, that won’t happen.

Could dialing back our profligate use of excess nitrogen have significant co-benefits for the climate problem?  I think the answer is yes, and that’s one question we explored in some depth this week.

Typically, in the climate science community, nitrogen is thought of as a valve on the rate of climate change.  E.g., more nitrogen means more of the greenhouse gas nitrous oxide…but also more plant growth (and hence less CO2) and more heat-reflecting aerosols.  Turns out the balance of all those things is probably about a wash, give or take  – at least in the short term.  In the long term, business as usual almost certainly means more warming from excess nitrogen, because of rising nitrous oxide levels.  But on the climate impacts side, less nitrogen is almost certainly a good thing right now.  Turn down the nitrogen faucet enough, and we might be able to worry less about what climate change is going to mean for clean air and clean water, and turn our focus to other challenges.

And the best news of all?  There’s all kinds of room to scale back our use of nitrogen (and phosphorus) without  threatening the main reasons we’ve messed with these cycles in the first place.  Thanks to regulations like the Clean Air Act, we’re driving more than ever….but seeing a decline in nitrogen oxides in the U.S.  The rest of the problem is mostly about growing food (and of late, biofuels).  In these realms, our efficiencies of nitrogen use are improving, but still not good.  Happily, plenty of evidence shows that we can do much, much better….without cutting down on the amount of crops we can grow.

Such were the kinds of issues we chased this week.  Our focus on climate and nitrogen was not only about the science of it all, it was because of the Congressionally mandated National Climate Assessment (NCA) that is now ramping up.  One of our goals from this meeting was to launch a process that can produce a formal report for the NCA.  One portion of the NCA process is a formal request to the community for scientific input – some of which may be used, some not.  In our case, we hope to produce a usable report that not only outlines the scope of the nitrogen challenges in the U.S. and why they matter for climate change, but provides some guidance to policy makers on how we might address those challenges…without turning U.S. socio-economic systems upside-down.

After a great week in Fort Collins, I think we are well on our way.  More info in the future as this process moves along.


One thought on “What can nitrogen do for you?

  1. John Freeland

    Good post, Alan

    “In our case, we hope to produce a usable report that not only outlines the scope of the nitrogen challenges in the U.S. and why they matter for climate change, but provides some guidance to policy makers on how we might address those challenges”

    Addressing the policy, it’s all about the incentives. Farmers are used to federal programs that pay them to behave.


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