This article by Lisa Lofland Gould first appeared in WildfloraRI, Winter 2018
In October 1988, the fledgling RI Wild Plant Society sponsored my attendance at a conference in Washington, D.C., The Consequences of the Greenhouse Effect on Biological Diversity. Among all the bigwig academic institutions, government agencies, and NGOs present at the conference, RIWPS was the only state plant society represented—kudos for foresight! My original article, a brief overview of the conference, is reprinted here, followed by a bit of commentary.
Scientists have been talking about the greenhouse effect for many years, but only recently has the term captured the public’s imagination, aided partly by 1988’s unusual summer of heatwaves and freak storms. That the greenhouse effect does exist is not seriously disputed, although its exact consequences are impossible to predict with current data. Just what is the greenhouse effect? When certain gases build up in the atmosphere, their increased presence has the effect of holding more of the sun’s energy within the atmosphere, rather than the energy radiating back into space. Carbon dioxide is the major component of the greenhouse gases, which also include nitrous oxide, methane, ozone, and fluorocarbons.
The amount of carbon dioxide in the atmosphere has increased about 25% since pre-industrial times and in the past 30 years has increased fairly dramatically. This trend is expected to continue during the next century (some predict a doubling of carbon dioxide within the next 50 to 60 years) and into the foreseeable future unless drastic measures are taken to control emissions into the atmosphere.
Most of this excess carbon dioxide comes from living things. Carbon dioxide is given off by the respiration of both plants and animals and is released when plant materials (such as wood) and fossil fuels (such as oil and gasoline) are burned. As the human population increases, so does the demand for advanced technology; the greater the use of technology by each person, and the larger the human popula- tion, the greater the release of greenhouse gases into the atmosphere. And the problem feeds on itself; the increase in greenhouse gases increases the temperature of the earth, which increases the speed at which living materials decay and release gases into the atmosphere.
All this might not be quite so bad, if it weren’t for another activity going on at the same time: deforestation. Just as the human population is growing and using energy at unprecedented rates, we are stripping the planet of the major absorbers of carbon dioxide, the forests. In a balanced ecosystem the amount of carbon dioxide released into the atmosphere is no more than the amount absorbed by plants during photosynthesis. Currently, however, there is an annual net increase of three billion tons of carbon dioxide into the atmosphere. If we could stop all burning instantly and reforest, it would reduce the annual carbon release into the atmosphere by 50%.
Scientists predict that this increase in gases in the atmosphere is changing global climate. Now climate change is nothing new; it’s been going on since the planet formed. Since the last ice age, about 12,000 years ago, the Earth has warmed approximately 5 degrees centigrade [41 degrees Fahrenheit]; if current predictions hold, scientists expect global temperature to rise by 3 to 5 degrees centigrade within the next 50 to 75 years. It is this rate of change that has scientists alarmed; what has been happening over tens of thousands of years will be occur- ring over a few decades and in conjunction with other global changes (such as acid rain and ozone depletion) brought on by human activity.
Predicting the extent of climatic change, where specific changes will occur, and how organisms will be affected, is much more difficult. Scientists are using computer models to make these predictions, but the models are only as good as the information put into them. In many areas of study, decades of underfunding in basic research have led to major gaps in our knowledge of ecosystems and how they function. In general, however, the models predict the following kinds of changes:
The Geosphere. Warming is predicted to be greatest at the highest latitudes (probably twice as great at the poles as in the equatorial regions) and to increase the most during winter months. This is likely to cause some melting of the polar ice caps and a rise in global sea levels of 30 centi- meters to 1.5 meters. (To put this in perspective, go to the beach and imagine the sea level 4.5 feet higher than it is at high tide; then imagine what coastal areas such as Florida would be like.) There will also be altitudinal climate shifts; for example, the present climate at 3000 feet of elevation on Mt. Washington in New Hampshire will be found (roughly) at 6000 feet.
Because the warming will not be evenly distributed over the globe, there will be changes in the circulation patterns of winds and ocean currents and therefore changes in rainfall distribution patterns. This moisture redistribution is predicted to produce less rainfall in the northern hemisphere and more in the southern hemisphere. Over the planet as a whole, there may be a 7–10% increase in rainfall. Weather patterns will become increasingly erratic, with an increase in the frequency of severe storms and new highs in storm surges.
The Biosphere. During the last ice age, spruce-fir forests, moving ahead of the glaciers, extended into the southern states; Rhode Island was covered with a sheet of ice. As the glacier melted, the boreal forest retreated north, leaving only scattered remnants on the highest peaks of the southern Appalachians. These forests had thousands of years to adapt to the changing climate, and even given this much time, many species—both plants and animals—became extinct. With a comparable climate change predicted for the next century, scientists have far more questions than answers about how the living world will be affected.
There is serious concern for any species that is slow growing, unable to migrate in the face of change, and/or has a limited habitat (which includes most of our rare species). Kirtland’s Warbler, for example, nests only in the Jack Pine forests of Michigan. If the climate changes as predicted, these forests will be gone by 2040, leaving Kirtland’s Warbler without its breeding site. For many species of trees, the mature tree can withstand a fairly broad range of temperature and precipitation, but the juvenile stages—the seeds and seedlings—tend to be much more sensitive, especially to changes in moisture patterns; this leads scientists to predict that some forests will lose diversity or change to other types of ecosystems. Overall, the composition of forests will change from within, with some species dying out in a particular area, and other species able to tolerate the changes.
As the vegetation changes, so will the animals and microbes. In the tropics, for example, many insects reproduce when certain plants are in flower or fruit; those plants, in turn, flower and fruit in response to seasonal rainfall patterns. We do not know if tropical plants will be able to change their reproductive patterns as rainfall patterns change, or if the animals that rely on the plants can make similar changes, but most scientist who are aware of the current “extinction spasm” occur- ring right now in the tropics are very gloomy about the tropics’ ability to with- stand the combined effects of deforesta- tion and the greenhouse effect.
The key issue for all organisms and ecosystems is their ability to respond to climate changes occurring at an unprec- edented rate. Species interact with one another in all ecosystems; nothing, includ- ing human beings, stands alone. The changes we expect from the greenhouse effect will influence all ecosystems, from the tropics to the poles, from the highest mountains to the oceans; and human endeavors will certainly be affected. Agriculture, fisheries, lumbering, and recreation are often mentioned, and there is concern over changes in where people will live, as both coastal waters and the human population rise. Climate change will bring shifts in the ranges of parasites and disease organisms that plague people and their livestock and crops. With human systems already failing miserably to feed, clothe, house, and heal the world’s people and giving even less respect to the rest of the planet, how will we respond to far greater pressures?
“We are headed into a new biological world,” stated one of the conference speakers. We cannot halt the climate chang- es—for the next fifty years or so, the stage is set—but we can work on slowing down the rate of change. The time has come for new ways of looking at the world. We can no longer view the planet as an endless source of resources for human beings to exploit but must take our place among all living things. If we act now, each of us can help heal the Earth.
As I reread this article, I was struck by how spot on the conference presenters were, those thirty years ago. Think of the intense hurricanes of the past decade or so; salt-water incursion on calm days in places like Miami and Virginia Beach; wildfires in the West; the movement of Dengue, West Nile, and Zika into temper- ate zones; and the fact that the 10 hottest summers recorded since 1880 all occurred since 1998. It’s now estimated that atmo- spheric CO2 has increased by 45% since pre-industrial times. The USDA revised its Plant Hardiness Zone Map in 2012 and entire states were placed in warmer zones. Arctic ice is melting, and scientific stations in Antarctica have had to move further inland, away from collapsing ice shelves.
Other pressures are also bearing down on the Earth’s ecosystems, as global trade has carried myriad species around the planet and increased the introduction of invasive species. Development and human population growth bring habitat destruc- tion and more impact on ecosystem health. While the Clean Air Act helped to reduce acid rain in North American waters and forests, oceans have experienced approxi- mately a 30% increase in acidity since pre- industrial times due to the interactions be- tween CO2 and calcium compounds. This especially affects shelled animals (think clams, oysters, corals, etc.), resulting in a huge impact on sea life and corresponding impact on people who rely on the ocean for jobs and food.
I could continue to update facts and figures, but the sentence that really struck me in that article was “That the greenhouse effect does exist is not seriously disputed.” Weren’t those the good ol’ days, when our nation’s leaders actually listened (sort of) to the scientific community? I don’t begin to understand how the political pendulum has swung so far toward irrationality and disregard for scientific process and data, but I fear that such attitudes are seriously compounding the problems we face.
But Hurrah for states like Rhode Island, whose Division of Planning now has an Executive Climate Change Coordinating Council and a Chief Resiliency Officer to help deal with climate-change challenges! Young people are also involved, via the RI Student Climate Coalition, as is the faith community—Rhode Island Interfaith Power & Light will hold its 10th annual interfaith conference on climate change this fall—and Rhode Island’s fine array of academic institutions and environmental organizations. Keep up the good work, folks. You are serving as a great model for other states to follow!
And to end on a happy note, thanks to management of Jack Pine forests and control of Brown-headed Cowbirds, the Kirtland’s Warbler population has actually increased in recent decades, and the warblers have been reported breeding in Wisconsin as well as Michigan. Let us all work toward ensuring that not all the direst predictions come true and help our citizens and leaders understand that forward movement comes not from denying reality but by facing it squarely.
Lisa Lofland Gould majored in Biology at the University of North Carolina and earned an MS in Zoology at the University of Rhode Island, where she taught biology for many years, was a research associate in the Department of Natural Resources Science, and a co-founder and first executive director of the RI Natural History Survey. She was also a co-founder of the RIWPS. Among other publications, she is a co- author of Vascular Flora of Rhode Island and Coastal Plants from Cape Cod to Cape Canaveral (UNC Press). Now that she is back in North Carolina, she enjoys participating in the Audubon Society of Forsyth County, Audubon NC, the Piedmont Land Conser- vancy, the Carolina Butterfly Society, and the NC Native Plant Society.