The Pluvial Continues… Has the Long Rain Epoch Begun?

by | 9.15.2013 at 9:04pm | 2 Comments
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It was midday. It was dark. It was June! It was pouring. We were sitting in my folk’s cabin in the Adirondacks when my dad groaned, “This is depressing”. Later on that same day, a hometown friend made a similar exclamation. Elizabeth’s update triggered a deluge of similar sentiments. During that discussion, she made reference to The Long Rain. It was the perfect comparison. Judging from the sentiment in our cabin, in the newspapers, and on Facebook, Central New York was on the edge of insanity because of the unrelenting rain.

A deluge during the Long Rain of June 2013 at Black Rock Forest. Photo: N. Pederson

A deluge during the Long Rain of June 2013 at Black Rock Forest. Photo: N. Pederson

 

It was too early in the season to write this post. Predicting future rainfall is like trying to predict Dennis Rodman’s next career move: It will move in a new direction, but no one can pinpoint the trajectory. But now, as Cortland and Macoun apples grace us with their presence, we can now safely say that summer is over (I do not care what the tilt of the Earth says. It is apple season!). In fact, the Northeast Regional Climate Center and NOAA have completed an early overview of this past summer’s climate. Their conclusion regarding precipitation in the Northeastern US? The Pluvial continues.

NOAA August and Summer 2013 summary of significant events. Hint: it was wet in the NYC region. Image from NOAA's climate summary page. Hat Tip to Stockton Maxwell for sharing this graphic with me.

NOAA August and Summer 2013 summary of significant events. Hint: it was wet in the NYC region. Image from NOAA’s climate summary page. Hat Tip to Stockton Maxwell for sharing this graphic with me.

 

Actually, these overviews typically discuss climate of just the most recent month or season year or versus the “climate normal.” While useful, these summaries do not paint the full picture. Consider this: A climate normal is often based on a recent 30-year period, like 1970-2000. Now consider this: Instrumental records for the Northeastern U.S. (below) and analyses for the Catskills region and southern New York State, here and here, indicate that since the 1960s drought, the region has seen a substantial increase in precipitation; in fact, hydroclimate seems quite unusual since 2000. Now really consider this: A tree-ring reconstruction of moisture availability indicates that the recent wetting comes at the end of a 120-180 year trend (and maybe longer). So, the daily comparisons on TV or other media sources are typically based upon recent climate and ignore the past. Thus, based upon paleo records, the full picture indicates that we are sitting in one of the more unusually wet periods of the last 500 years.

Northeastern US summer precipitation from 1895-2013. 2013 is the second wettest summer on record for the entire region. Data and image procured from NOAA.

Northeastern US summer precipitation from 1895-2013. 2013 is the second wettest summer on record for the entire region. Also note the only two years since 2002 are below the average since 1895. And, they are marginally below the mean at best. Data and image from NOAA.

 

I return to this topic because of: 1) the many implications of this climatic shift and, most importantly, 2) what seems to be a limited amount of public awareness of how wet it has become in recent decades (though this awareness is growing). The substantial change in moisture across the Northeastern U.S. (the draft of the 2013 3rd assessment is here) is more commonly known in the scientific literature, but it seems to be less well-known outside of that community. For example, under the tab “Climate Change” on the Northeast Regional Climate Center’s excellent web resource, one can only find minimum and maximum temperatures when seeking to understand how much the climate has changed. An increasing trend in precipitation just doesn’t seem to grip the attention of most people like an intense heat wave or drought. In fact, an editor remarked to a freelance writer that they’d only do a story on the change in precipitation in the NYC region if “they were painting the lawns green on Staten Island.

For the people in Vermont, the Catskills, Mohawk Valley, and those wishing to use beaches in the summer along the coast, this seems a bit short-sighted. Excess rain is costly. It costs the people still trying to rebuild in the Catskills from the flooding of 2011 (and it isn’t just the two tropical storms that triggered the flooding – new research indicates that because the soils were saturated, the impact of Irene and Lee were worse than they might have been in other times). It costs people in Vermont wanting to rebuild their cultural heritage. It will cost all of us in NY State if tax breaks are given to expand flood relief measures in five counties and restoration and reconstruction of managed water systems; climatic change disregards political boundaries. It might cost us if we are managing forests for a long-gone climatic era. It further erodes trust between country and city folk as well as citizens and their government. Tragically, it costs lives.

So, as we become aware of the impacts of additional rainfall (and certainly there are additional costly impacts than what is listed above), we need to know that precipitation is likely to increase over the coming century. Model projections indicate it is likely that the Northeast will get wetter and have more extreme rain events. This doesn’t mean we will not experience droughts in the future, nor does it mean each summer will be like 2011 or 2013. And, these model projections could be wrong. But, our state of knowledge indicates that these Long Rain conditions could become more common.

This shouldn’t be viewed as more environmental doom and gloom. Humans have enormous brains and know how to use them! See: Klaus Jacob. We have the ability to prepare for potential adversity. And, if it isn’t clear by now, humans are one of the more adaptable and flexible animals on the planet. Heck, we might even celebrate wetter conditions with some enormous fun. And, from my Broadleaf perspective, the Northeast could become a temperate rainforest with bigger trees and a denser forest.* Folks spend enormous money to experience such things.

Dario Martin-Benito and Javier Martin-Fernandez in the Oriental beech dominated Colchic temperate rainforest in the Mtirala National Forest of the Republic of Georgia. Photo: N. Pederson

Dario Martin-Benito and Javier Martin-Fernandez in the Oriental beech dominated Colchic temperate rainforest in the Mtirala National Forest of the Republic of Georgia. Photo: N. Pederson

 

 

 

 

 

 

* unless future warming overwhelms our rain wealth and stunts the future forest…. apologies. It is hard to avoid all of the potential doom and gloom…

 

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2 Responses to “The Pluvial Continues… Has the Long Rain Epoch Begun?”

  1. Alissa says:

    Thanks for the informative essay! I’m interested in modeling how tree growth responds to climatic (and possibly biotic) changes. I hadn’t thought of changes in growth that may occur from an overall increase in precipitation on the east coast…I wonder if anyone has tried to predict this before? It seems like the focus tends to be on how trees respond physiologically to higher temperatures and/or drought conditions. Regardless, thanks for the blog!

  2. Thank you, Alissa. I think you are generally correct. During my dissertation, for example, I focused on the climatic response of southern temperate tree species at northern range margins with a particular focus on temperature. For broadleaf species, the limitation of cool temperatures mattered much less when compared to conifers: http://goo.gl/4yIXcn ; I’m pretty sure Ed Cook anticipated this result. With the greater awareness of the ecotonal shift and mortality of trees as the result of a heat-exacerbated drought in the southwestern US during the 1990s [http://www.pnas.org/content/95/25/14839.long ], drought is now being seen as having a greater impact on many tree species in a variety of ecosystems around the globe: http://www.nature.com/nature/journal/v491/n7426/fig_tab/nature11688_ft.html – so, in the case of increased moisture in the eastern US, it would seem that this could be a positive factor to growth (until/unless temperature overwhelms the increase in moisture abundance).

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