Why It's Climate Change and Not Global Warming and Why It Matters

Let me start this post by saying up front that, as a scientist, I believe that human activities over the past 200 years have resulted in a global warming trend that has been more rapid than any that we’ve seen in the paleoclimatological data to date. And I believe this current warming trend is setting us up for changes in our global climate that will continue way beyond our own lifetimes and will cause major disruptions in the lives of millions of people.

I try to avoid arguments on Facebook with climate change skeptics. Although sometimes I try to politely point out when their comment makes an incorrect assumption or draws an unsupported conclusion about climate science. And then someone else will often chime in trying to hijack science to support their view that climate change is a hoax or a conspiracy by ________ (fill in the blank with whichever liberal the person dislikes the most). I experienced a Facebook exchange just like this yesterday. Most of the time it’s people confusing weather with climate. Weather is what we experience day to day and differs from town to town. When we talk about climate, it’s on a global scale and trending over one year or thousands of years. Climate is driven by complex interactions of ocean currents and ocean temperatures with ambient air, resulting in the range of temperatures and range of precipitation experienced of over a given span of time at any given point around the world. That’s why I prefer to call it Climate Change. If I say global warming, someone will always point out that we just had one of the harshest winters in southeastern PA since the late 1970s.

The Facebook exchange started when one of my conservative friends posted a link to a climate-denier’s blog that discussed Antarctic sea ice levels increasing despite a warming global climate. Of course both the blogger and my friend took this sea ice observation as proof that global warming is a sham. So I took his bait and responded with the following analogy.

Trying to understand climate change is like watching a 5-hour long movie frame by frame. A human lifetime would equate to seeing one or two frames of that 5-hour movie. For a 21^st century human to say that they do not see the climate changing is like viewing one or two frames of the movie and saying you don’t see a movie. To get an idea of what the movie is about, you’ve got to rewind through at least the previous hour. And that’s the case with climate change – you’ve got to look back at previous cycles of natural climate change to make sense of the rate of temperature change seen over the past 200 years since the start of intensively burning fossil fuels.

Then someone else tried to refute me by posting a graph showing ambient temperatures going back 10,000 years that were calculated from ice cores collected in Greenland. The graph came from an academic paper and was supposed to prove that it’s not as warm now as it has been for the past 10,000 years. Unfortunately, that individual was cherry picking data that was collected for an entirely different purpose than solving the global warming debate.

The graph in question was from a paper by Dr. Richard Alley, a widely respected glaciologist from Penn State. I had the opportunity to hear him lecture once when I was in grad school at Lehigh University, because he was a frequent collaborator with one of my professors. As esteemed as Alley is as a glaciologist, he would not claim to be a climatologist. So I looked up the abstract for the paper that this graph comes from, because I was curious about its context.

The title of the paper is, "The Younger Dryas cold interval as viewed from central Greenland." The Younger Dryas cold interval was a period from approximately 12,800 to 11,500 years ago in which the earth experienced a temporary period of cold, dry conditions. This 1300-year interval was at the tail end of the overall warming trend associated with the end of the most recent glacial period, which officially ended about 10,500 years ago. Alley would likely study the Younger Dryas to determine its effects on Greenland’s glaciers at that time. At the glacial maximum for the most recent glacial period (about 22,000 years ago), the glaciers had advanced about as far as Blue Mountain in eastern PA, Long Island, NY, and across many of the northernmost states in the Midwest. So the Younger Dryas period was a 1,300-year anomaly in the final 11,500 years of the most recent glacial period.

So in the big picture, yes, we are simply somewhere in the middle of one of several interglacial periods in the earth's 4.6 billion year history. But there is a preponderance of evidence indicating that carbon loading into the atmosphere appears to have accelerated the natural warming trend that we probably were already in. Indisputable proof doesn’t happen often in science, so we have to rely on the general conclusions of the overwhelming majority of climate scientists. Their climate models all vary to some extent, but most of them acknowledge the effect of man-made carbon tweaking the global climate and accelerating the rate of warming of our oceans and atmosphere.

The reason for concern is that the temperature increases we are seeing in our global climate over the past 200 years have been at a more rapid rate than the warming period from 22,000 to 10,500 years that ended the most recent glacial period. There is evidence to suggest that during the previous interglacial period, around 125,000 years ago, sea levels were 3-4 m higher than they are presently. So if our present interglacial period ultimately gets as warm as the one that peaked 125,000 years ago, we could be looking at sea levels rising 10-12 feet. Even a couple of feet over the next 100-200 years is going to displace millions of people.

And possibly an even more immediate concern is feeding the earth's 7 billion people when weather patterns shift and droughts become more prevalent in regions currently associated with agriculture. The eastern U.S. might get wetter as a result, but we've built on or paved much of our great agricultural soil in the east over the past 50 years. The threat to agriculture is one reason that the U.S. Department of Defense considers climate change a national security threat.

Of course, the explanation above, when offered on Facebook, was met with the usual accusations of academic dishonesty by the 95% of climate scientists who will say anything just to get more funding to perpetuate the hoax that the “Administration” wants people to believe. But at least our military is acknowledging the worst case scenario of a climate warming more rapidly than it appears to have over the past couple hundred thousand years. So I guess we need to modify that old adage that the two things to never discuss at a cocktail party are politics and religion. Regretfully, it seems that we need to add science to that list of taboo topics.

Rock Snot - Coming to a River Near You

Have you been concerned about didymo (a.k.a. "rock snot"), the algae that seems to be slowly taking over waterways throughout the northeast? A study from the University of New Brunswick, recently published in the Canadian Journal of Fisheries and Aquatic Sciences, offers both good news and bad news about didymo’s spread.

Didymosphenia geminata (www.mdinvasivesp.org)

Didymo is an algae (technically, a diatom) that forms a dense mat on the bottom of swiftly flowing freshwater rivers and streams. As its nickname implies, it looks a bit like a thick, gooey layer of mucous covering the bottom of streams and rivers. It can smother other aquatic vegetation, reducing habitat for the aquatic macroinvertebrates that fish feed on. In the past two decades it has been identified in the waters of the U.S., Canada, New Zealand and Europe.

First, the good news. Especially for anglers and boaters. Up until now, the conventional wisdom was that didymo was an exotic invasive algae species that was hitchhiking between watersheds on anglers’ gear, especially felt-soled wading boots, and on boats. State environmental agencies have launched intensive educational campaigns urging anglers and boaters to wash their gear and let it dry thoroughly to prevent further spread of didymo. Washing gear with a bleach solution was recommended. But according to the University of New Brunswick study, anglers and boaters are not spreading anything that was not already in their local ecosystems. So if anglers and boaters are not to blame for the ooze of algae popping up in more and more watersheds, what is going on? Sit tight for the bad news.

The didymo study looked at archival samples of lake sediment from several regions in Canada, and they found that didymo has been in these ecosystems for quite some time. Evidence of didymo can be found in the sediment record back to the beginning of the 20^th century and possibly even the last decade of the 19^th century. The researchers found that even in ecosystems which did not necessarily have evidence of didymo, there were increases in other algae species at approximately the same rate that didymo was increasing in lakes where it was present. The researchers found that increases in didymo and other algaes appeared to correlate with the warming climate. The study leader, Michelle Lavery, said, "We can't make any solid claims as to what the mechanism is that is favoring didymo, but we strongly suspect it has to do with climate." So although anglers and boaters seem to be off the hook for spreading didymo, the awakening of dormant didymo in bodies of water potentially throughout North America by a gradually warming mean global temperature would mean that we have little hope of preventing didymo from appearing in a river near you. That’s the bad news.

So does this new view of didymo mean that anglers and boaters don’t need to sweat about washing down their gear between destinations? No. There are other aquatic nuisance species that are much better understood than didymo that can hitchhike on our gear. Zebra mussels are one prominent example. So keep scrubbing down between trips.

I think the take-away message from this study is that didymo is still going to be a concern for those of us who rely on healthy and diverse waterways for our outdoor recreational fix. Although the indication is that anglers and boaters are not spreading it, this new study suggests that didymo may continue to appear throughout the waterways of the traditionally cooler regions of North America as long as the mean global temperature continues to inch up. I suspect that these findings mean that researchers can now focus their future didymo studies looking for ways to minimize inevitable didymo blooms under the assumption that it is already present but dormant in most aquatic ecosystems. And for anglers who will have to adapt to wading through dense patches of slippery rock snot? Maybe it’s time to invest in a wading staff.

Sources:

http://www.cbc.ca/m/touch/canada/newbrunswick/story/1.2554825

http://www.mnn.com/earth-matters/wilderness-resources/stories/whats-causing-canadas-rock-snot-infestation

http://phys.org/news/2014-02-debunk-argument-invasive-algal-species.html

Climate Change From a Fish-eye View

For those of us who acknowledge that climate change is real and is already happening, we have the advantage of planning ahead to identify actions that we can take on a local scale to alleviate some of the effects we expect to see throughout the rest of our lifetimes. The U.S. Congress and global diplomats certainly have the ability to take much bigger strides to try to mitigate a climatic tailspin by taking action to lessen the amount of carbon dioxide going into the atmosphere. But let’s consider something each of us can do to mitigate some of the CO2 already in the atmosphere. Plant trees.

A shade tree is capable of absorbing and storing as much as 48 pounds of CO2 in one year. In 40 years, a tree can sequester one ton of CO2 (http://www.ncsu.edu/project/treesofstrength/treefact.htm). That’s pretty substantial, especially considering that most large shade trees (non-ornamentals) can live decades beyond 40 years.

I have a feeling that not very many climate deniers are going to be reading this post. But just in case, for their benefit, I’ll point out another important benefit of planting more trees in our communities. Stormwater control. Trees can manage some of the stormwater heading for waterways in two ways. First, they intercept rainfall before it hits the ground. The result is a delay in the rain hitting the ground as it hangs out on the vast surface area of the leaves and bark. Think about how often you’ve walked under a tree after a rain shower and had raindrops fall from the leaves onto your head and shoulders. And more significantly, trees consume huge amounts of stormwater after it hits the ground. A mature oak can consume up to 40,000 gallons per year. Decreased stormwater runoff means less severe flooding. It’s estimated that for every five percent increase in tree cover in a community, the stormwater runoff is decreased by approximately two percent (https://www.americanforests.org). A two percent decrease might not sound like much, but for municipalities trying to meet the requirements of their EPA stormwater discharge permit (Municipal Separate Storm Sewer System, or MS4, permit), every gallon that doesn’t go into the local creek is a welcome reduction. Trees also absorb some of the pollutants picked up by stormwater, keeping them from washing into waterways as well. See, trees have something to offer everyone regardless of their climate beliefs.

So, speaking of trees, my local Trout Unlimited chapter (the Little Lehigh Chapter) last week was awarded a 2014 Coldwater Conservation Implementation Grant from the Coldwater Heritage Partnership. The Coldwater Heritage Partnership’s mission is to provide leadership, coordination, technical assistance, and funding support for the evaluation, conservation and protection of Pennsylvania's coldwater streams. The partners are Pennsylvania Fish and Boat Commission, Pennsylvania Department of Conservation and Natural Resources, Foundation for Pennsylvania Watersheds, and Pennsylvania Council of Trout Unlimited. The chapter will use this $5,172 grant to purchase and plant 76 appropriate shade trees throughout five selected areas along the Little Lehigh Creek in Lower Macungie Township that have significant gaps in the streamside riparian buffer tree canopy. As they mature, these shade trees will help to maintain the naturally cool water temperature in the spring-fed Little Lehigh to help prevent heat stress on the native trout during the summer months.

 

Little Lehigh Creek at Willow Lane in East Texas, PA. 

But this grant award is a win for more than the Little Lehigh’s native trout. As the trees grow, they will be sucking up stormwater runoff heading for the creek along with some of the road salt, fertilizer, oil and grease typical in suburban stormwater runoff. And, by 2054, these 76 trees will have absorbed approximately 76 tons of CO2 from the atmosphere.