Evolving Spring: Plant and Animal Vulnerabilities to Climate Change

Why do many of us believe that there is a serious problem heading our way called climate change? It's not a matter of blind faith. Like evolutionary theory it is an increasingly supported hypothesis based on a commensurate body of evidence. "Plants earlier bloom times hurting some creatures" reads the title of a recent Washington Post article by Brigid Schulte. See http://www.washingtonpost.com/local/plants-earlier-bloom-times-hurting-some-creatures/2011/04/08/AF42He4C_story.html. It goes on to describe field botanists' surprise that some flowers like “Dutchman’s breeches” and cut-leaved toothwort are blooming 2 weeks early. The culprit is global warming:

"Bloom hunters like Fleming, who for 40 years have been tramping through the woods, roaming along riverbanks and scrambling over rocky outcrops to document the first blooms of spring in the Washington area, worry that what they have been seeing is nothing less than the slow, inexorable shift of global warming.

They even have a name for it: season creep. And it’s happening all over the world."

Some causal evidence is experimental and comes from labs. A recent Science Friday show (http://www.sciencefriday.com/newsbriefs/read/200) made this point citing data from the University of Melbourne on the Australian common brown butterflies (heteronympha merope). They are emerging from their cocoons an average of ten days earlier than they did 65 years ago. The researchers attribute the butterflies’ early appearance to warming temperatures in the region. To test this they raised caterpillars of the common brown butterfly in a lab and then measured how quickly they emerged when exposed to different temperatures. The warmer the temperature, the earlier the butterflies took flight. They then used these measurements along with historic records of air temperatures around Melbourne, which rose about .25°F per decade, to predict when the butterflies emerged each year. Their predictions closely matched recorded observations. They concluded that:
"warming temperatures are coaxing the butterflies around Melbourne from their cocoons earlier each year, at a rate of about 1.6 days per decade."
(Photo by Flickr user Ibsut.)

The researchers believe the change in temperature is the result of human greenhouse gas emissions, not climate variability. A steady trend supported by 40 consecutive years of research at the Rocky Mountain Biological Laboratory also shows a warming trend. Flowers are blooming a month earlier than just 10 years ago. This is not all good for them, since some bloom early enough to be killed off by a late frost. That's another part of the problem, a trend towards greater weather variability. That's something easy to intuit since things are changing to a new normal. See http://www.sciencefriday.com/blog/2011/04/2031/ for a long list of evidence for climate change.

Biological warning signs of change are numerous and easily documented since many cultures have finely tuned agriculture to depend on spring for a release from winter famine. Cultures like the Korean have long records of when the first cherry blossoms of spring arrive and there is a 300 year European record on when grapevines bloom since planting time is critical to a good harvest.

A summary graphic in the Post shows how many plant species in the DC area are"creeping earlier" into spring. Bad for us, and it also has worrisome consequences for the naturally evolved plant and animal world. Evolution has fine tuned seasonal timing for many species. Our local squirrel population is dependent on the nut harvest to get them through winter. They have a frantic winter breeding seasons where females are in estrus for just 8 hours, but it results in spring-born squirrel babies (March to May) when there is again a natural supply of food. But some species in the complex chain of interdependence have been unable to keep up when seasonal timing is off.

In Europe, the leaves of the English oak are coming out earlier and this is OK for some animals. The winter moth caterpillars that feeds on them are also coming out earlier. But the pied flycatcher birds that eat those caterpillars aren't year around residents. They are migrating north at that time. Now when they arrive, many of the the caterpillars have already turned into moths and have flown off. It's a delicate ecological balance and changed timing has resulted in a severe decline of flycatcher population in recent years.

In San Francisco, some butterfly populations like Edith’s Checkerspot butterfly are simply gone. With the gradual warming of Earth and ocean temperatures that has also shifted rainfall patterns, the leaves of the plantago plant come out earlier. The leaves, which the checkerspot caterpillar depends on for food, are already dried and withered by the time the larvae emerge.

It's a deadly problem for migrating and seasonally dependent animal species. Even the largest creatures alive on the planet are affected - giant trees like our redwoods. A recent study finds that declining fog cover on the California's coast could leave the state's famous redwoods "high and dry." Among the tallest and longest-lived trees on Earth, redwoods grow where the summer fog provides water. But the fog is diminishing and climate change seems to be contributing to this decline in a high-pressure climatic system that lingers on the coast. See http://news.nationalgeographic.com/news/2010/02/100215-redwoods-california-global-warming/+.

Plant evolution has produced wonders, but unlike animals, they can’t just get up and relocate. The speed of change is something that vast numbers of species may fall to. Something to think about amidst this year's blossoms.

It was the worst of times, it was the most challenging of times

I think of myself as an optimistic sort. But it's hard to be upbeat and optimistic just now, while laying claim to realism. The post-earthquake tsunami off the coast of Japan smashed lives, towns and much more. It is remarkably inspiring to see how focused the Japanese people and institutions have been in response with orderly queues and patience. But it also suggests how vulnerable we are and how insecurely we live in a natural world that is not specifically designed for perpetual human flourishing. We have to adapt and respond responsibly to the world and its dangers as we come to know them. Some dangers we have a hand in manufacturing for ourselves. We like to live on the coast, and so developers have made it attractive to do so. But in some places it is dangerous. With little long-term perspective we gamble big time with lives and investment. Perhaps there is an evolutionary reason for this - it has been adaptive in the past.

Evolution has given us an adaptability to many environmental dynamics. But not on the scale of geologic events and not of the scale that we may now be able to precipitate ourselves. In crises like earthquakes and tsunamis we are faced with difficult immediate choices – Do we flee the building, do we run to a car and head for higher ground by a main road, which may be jammed, or do we walk there immediately? On foot, we can't travel very far, but what if a tsunami hits before we made it to our vehicle? We might get far enough by foot while the extra time to get to a car may be critical. We just don't know what is reality in the face of some crises. It is easy to feel helpless.

So human decision making is not always up to the challenges of immediate crises, but there is another type of crises to consider. We may not be up to the challenge of slowly developing crises that we ourselves are causing. We seem to have lots of gambles going now as much goes wrong in the natural, political,financial and international spheres. Lurking in the back of consciousness is the idea that we have these long-term gambles going along with a mega gamble on climate change.

Tsunamis arrive within minutes and but climate change could put us in hot water that is just as deadly and much longer lasting. I heard a vivid image of such a hot world described by Mark Hertsgaard, The Nation's magazine's environmental correspondent. The ideas were from his new book "Hot: Living Through the Next 50 Years on Earth" by (see http://www.climatesciencewatch.org/2011/01/29/hot-living-through-the-next-50-year/ for a review). Using a variety of experts Hertsgaard envisions how day-to-day life might change, for what he calls Generation Hot, in the next 5, 10, and 50 years. For Generation Hot, the brutal summer of 2010 was part of the new normal for their future.

In Hot he describes a Chicago with the climate like Houston's. There is crop damage to prairie and California due to drought and snow pack melt off. Such things as extraordinary heat, rains, drought and flooding that occurred in the summer of 2010 are projections from the U.N.’s World Meteorological Organization and they fit the U.N. Intergovernmental Panel on Climate Change’s projections of “more frequent and more intense extreme weather events due to global warming.” We face a series of crises and the tsunami floods we see today in Japan may be emulated by stronger tropical storms of the next 50 years.

But listening to Hertsgaard the situation is not yet like the helplessness caused by the tsunami. His "pictures" of what to expect, includes creative precautions and that's what we need in the face of a challenging reality. We may be able to understand the situation enough to meet what he calls the“double imperative” of the climate fight. “We have to live through global warming,” he writes, “even as we halt and reverse it.” One part are initial priorities that experts call “mitigations” like deep emissions cuts . The other is to do everything we can to prepare for the inevitable effects of the climate change currently "baked in". Hertsgaard leverages the thinking of people like King County executive Ron Sims (who now is the deputy administrator at the U.S. Department of Housing and Urban Development). Sims has worked on the redesign needed to adapt to climate change in urban areas like Seattle, Washington. In the light of recent catastrophes there are cautions to consider. In Hertsgaard we hear a motivating message mixing concern with cautious hope. Something to consider as we face the immediate crises.

As a youth I read quite a bit of science fiction which is often upbeat about human possibilities. But one hard SF writer Larry Niven added notes of caution for our future. Taking an alien perspective (Trinocs) of human psychology, Niven's fictional character comments that "humans are insufficiently suspicious" of possible threats. From an alien perspective we seem much to anxious and ready to gamble with our survival in situations where we have no idea of the odds. The Trinoc wonders how we "have survived up till now(from A Hole in Space). Maybe by luck, but now we have to be doubly wise.

See also http://www.thenation.com/video/158886/climate-change-deniers-arent-skeptics-theyre-cranks for his critique of climate deniers).