The presence of small amounts of heat-trapping greenhouse gases in the atmosphere warms Earth's surface, resulting in a planet that sustains liquid water and life. Jump to Greenhouse Gases Make the Earth Habitable
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What You Need to Know About Principle 3: Life Affects Climate, Climate Affects Life
Plants and animals, even microorganisms influence climate. They have also been influencing the Earth’s climate for billions of years, ever since microbes began changing the atmosphere.
This principle is about the relationship between the biosphere and the climate system, including the annual changes in the amount of carbon dioxide (CO2) in the atmosphere. Annually, the amount of CO2 increases in the spring and summer months and decreases in the winter because during the growing season plants use photosynthesis to draw CO2 from the atmosphere and release oxygen. Click the tabs below to learn more about how climate and living things interact.
Individual Plant and Animal Species Require Specific Climatic Conditions to Survive
Individual organisms survive within specific ranges of temperature, precipitation, humidity, and sunlight.
Organisms exposed to climate conditions outside their normal range must adapt or migrate, or they will perish.
Scientists have a special term to describe changes in an individual organism over the course of its lifetime: phenotypic plasticity. That's a mouthful, but the idea is straightforward. An organism's phenotype is simply its set of features, and to be plastic means to be moldable or changeable — so phenotypic plasticity just means that an organism's features can be molded, or influenced to some degree, by its environment.
A grizzly bear changing its diet from berries to apples or corn during bad berry years is an example of phenotypic plasticity because it did not require a genetic change. Even though the bear did not evolve with corn or apples, it can change its diet to take advantage of them.
This is different from genetic adaptation, which involves a genetic change or mutation that becomes dominant through natural selection. An example would be a rabbit that grows white fur in the winter and brown fur in the summer, a genetic trait that was selected for because it improved the species’ survivability. Read More…
This Creepy Map Shows Just How Early Spring Is Coming to Your Area This Year
Click the map to learn more
Greenhouse Gases Make the Earth Habitable
Heat-trapping greenhouse gases are not all bad.
In fact, their presence in small amounts in the atmosphere makes life on Earth possible. That’s because they warm the Earth's surface, resulting in a planet that sustains liquid water and life.
Earth is the Goldilocks planet: “not too hot, not too cold, but just right” for liquid water to exist. Read more…
Changes in the Climate can Affect Ecosystems
Changes in the climate can affect the health of ecosystems and the survival of entire species.
The distribution patterns of fossils show evidence of gradual as well as abrupt extinctions related to climate change in the past.
The Earth has experienced at least five major mass extinctions in the past when the climate and/or environment shifted.
Some scientists suggest we are in the midst of another mass extinction, this one caused by human-caused climate change.
Over billions of years, organisms have been able to adapt to and evolve with the changing circumstances. But changes, especially in terms of temperature and precipitation, can spell the end of individual organisms and sometimes entire species.
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Preventing the Sixth Mass Extinction Requires Dealing With Climate Change Photo credit: David Smith, University of California Museum of Paleontology
Source: Huffington Post: Posted: 11/18/2014 7:37 pm EST Updated: 01/18/2015 5:59 am EST
Last week the United States and China signed a landmark agreement to combat climate change. This is an important step in guarding against even more damage from rising seas that threaten major cities, increasingly common and severe storms that devastate lives and property, wildfires, drought, and the huge economic costs that already are mounting from climate catastrophes.
However, from my perspective as a paleontologist who has spent decades studying the impacts of climate change, both before and after people got into the act, there is an even bigger reason to forge global climate agreements. Allowing the climate change we're now causing to continue would virtually guarantee that human beings will be the first species in the planet's history bring on a mass extinction of life on Earth.
Mass extinction means that at least three out every four species you are familiar with die out. Forever. Extinction of that magnitude has happened only five times in the past 540 million years, most recently 66 million years ago, when the last big dinosaurs were killed by an asteroid strike.
Today, even without human-caused climate change thrown into the mix, most scientists agree that we — Homo sapiens — have been pushing the world towards the sixth mass extinction from such long-recognized human pressures as habitat destruction (for instance from deforestation or pollution), poaching, and overfishing. The magnitude of those pressures is overwhelming when you start to think on the global scale. We've completely plowed, paved, or otherwise transformed 50 percent of Earth's lands, taking all those places out of play for the species that used to live there. With 7 billion of us (and more added every day) on the planet, the human race now takes more than a third of all the energy produced by plant photosynthesis — so-called net primary productivity — just to support itself. That means a third less energy is available to sustain life for all the other species on the planet.
The International Union for the Conservation of Nature has determined that, as a result of such pressures, at last count, well over 20,000 species are now threatened with extinction. That is more than a quarter of all evaluated species. Of course, the actual number of species hanging on by a thread is likely much higher, given that many species have not even been evaluated yet.
Adding today's human-caused climate change -- and especially the accelerated changes projected under business-as-usual scenarios -- into the milieu of extinction drivers is like adding a match to gasoline. One reason is that the planet is rapidly heating up to a temperature that most species on Earth today have never experienced. For example, never in the 160,000-year history of the human species have we seen an Earth as hot as it will be by mid-century. Keep that warming going until the year 2100 and Earth would be hotter than it has been in the past 14 million years; that is the trajectory we are now on. Most species alive today, however, have only evolved to cope with climatic conditions that have existed over the past 2 million years.
The rapidity of human-caused climate change is the second big problem causing extinctions. Today, climate is changing at least 10 times more quickly than living species have ever experienced in their evolutionary history. That means that evolving to cope with the newly emerging climatic conditions is not an option for most species, because evolution has a speed limit usually reckoned in thousands to millions of years. Evolving to meet such a severe climate challenge over a hundred years or so simply exceeds most species' adaptive capacity, ultimately because genetic mutation rates are so slow. The exceptions — the adaptive winners in the climate change game, if you will — are species that reproduce quickly and in prodigious numbers, like flies, mosquitoes, rats, and mice.
Easier than adapting, of course, is simply up and moving, which species have been known to do during past times of climate change, though none of those past climate changes was as rapid as what is happening today. But even in cases where species could theoretically run quickly enough, on today's landscape, and especially given the shifting climatic regimes of the coming decades, there is nowhere to run to. Not only are the few remaining patches of habitat that contain diverse species separated by impenetrable human-modified and human-dominated landscapes and seascapes, but ongoing climate change promises to steal the very habitats that now support most species on the planet. On land, as much as two thirds of all species live in tropical and subtropical forests, yet climate models indicate that by the time babies today are middle-aged, the climate required to support those tropical and subtropical species will disappear over large swaths of the lands where they currently live and will be found nowhere on Earth.
In the oceans, it looks every bit as grim if we do nothing to slow climate change. Both experimental and modeling research indicates that warming waters and the other byproduct of elevated greenhouse gases, rising acidity in the oceans, would likely cause coral reefs to disappear almost entirely by 2070. These "rainforests of the sea" support 25 percent of all the ocean's species -- and 10 percent of the world's fisheries, which provide the principal protein for hundreds of millions of people and inject billions of dollars per year into the world economy.
Avoiding such dire scenarios requires a multi-pronged effort to address all known extinction drivers -- including protecting remaining habitats, halting poaching, cleaning up pollution, slowing and stabilizing human population growth, and ascribing economic value to biodiversity in general and to keeping species like elephants and tigers alive rather than selling their bodies for parts. And indeed, efforts focused in those directions have proven successful in bringing some species back from the brink.
But human-caused climate change has fundamentally changed the extinction game to one we are destined to lose if we simply continue business as usual. The only way to prevent the extinction of thousands of species will be to slow greenhouse warming dramatically, which requires rapidly shifting from a fossil-fuel economy to one dominated by carbon-neutral energy. Numerous analyses have shown the technology and expertise exists to make this possible. All that's standing in the way is deciding it's the right thing to do.
It is still unclear whether the world is ready to do anything about climate change. The follow-up to last week's historic climate agreement between the United States and China will be telling. And while it's appropriate that world leaders are weighing the immediate human impacts against the costs of climate action, it's also essential that they, and the rest of us, see the bigger picture. The most critical accounting needs to be reckoned in lives, not only of individuals but of entire species. That accounting under a business-as-usual scenario rapidly adds up to the sixth mass extinction. And, while many impacts of climate change may come and go and vary from place to place, extinction is forever.
Anthony D. Barnosky is a professor in the Department of Integative Biology, a curator at the Museum of Paleontology, and a research paleoecologist at the Museum of Vertebrate Zoology at the University of California, Berkeley. His new book, Dodging Extinction: Power, Food, Money, and the Future of Life on Earth (University of California Press, fall 2014) explains how we can get climate change and other extinction drivers under control to avoid the sixth mass extinction. He also talks about these issues in the upcoming film Mass Extinction: Life on the Brink, to be released on the Smithsonian Channel Nov. 30.
Photo credit: David Smith, University of California Museum of Paleontology
Over Most of the Last 10,000 Years, the Climate has been Unusually Stable
A range of natural records shows that the last 10,000 years have been an unusually stable period in Earth's climate history.
Modern human societies developed during this time.
The agricultural, economic, and transportation systems we rely upon are vulnerable if climate changes significantly. Read More…
Life on Earth is a Major Driver of the Global Carbon Cycle
click the image to enlarge it and read about stromatolites
It does so by modifying the chemical makeup of the atmosphere. The geologic record shows that life has significantly changed the atmosphere during Earth's history.
Observed Changes in Phenology Across
the United States - Southeast
Virginia, Kentucky, Tennessee, North Carolina, South Carolina, Georgia, Florida,
Alabama, Mississippi, Louisiana, Arkansas
Land cover of the Southeast is characterized by productive forests, mountains, and extensive wetlands and shorelines. Climate is humid and subtropical, with the tip of Florida classified as tropical with wet and dry seasons. The large wetlands in the Southeast are especially vulnerable to predicted shifts in water levels, which could inundate critical regions such as the Everglades. This region is also susceptible to hurricanes: these storms are expected to become more intense with increasing ocean water temperatures. Since 1970, the annual mean temperature of the region has increased by nearly 1.1°C (2.0°F), with most of this warming in the winter.
Over the past century, the Southeast has experienced significant growth in urban areas, increased evaporation and cloudiness from increased temperatures, and a general cooling trend until 1980 when temperatures began to increase. The last hard freeze dates have become significantly later from 1901-present, on the order of more than 1 day/decade. The so-called “warming hole” (an area centered across the southeastern U.S. where warming is happening at a slower rate than elsewhere in the U.S.) has recently been linked to decadal variability in the Pacific Ocean.
Changes in Phenology - Highlights
Delays in plant leafing and flowering
In contrast to many parts of the U.S., plants of the Southeast on average are experiencing, and likely will continue to experience, delays in leafing and flowering. This may be due to a lack of sufficient chilling days due to increasing temperatures. This may result in a delay in spring budburst for plants that require this chilling period. Herbarium specimens collected in Florida from 1819 to 2008 showed a delay in blooming (with a range of four to 19 days later than the beginning of the dataset) for both native and nonnative species. Research has linked this delay to within-year variability in minimum temperatures, suggesting that the physiology of the examined species may be connected to changes in minimum temperatures.
Timing of bird migrations in flux
According to 40 years of data on birds migrating between the northeastern U.S. and Louisiana, the interval between capture dates across the migration route has become shorter in warm years and longer in cold years. This suggests that the long-distance migrants may have the capacity to adjust their migration times relative to changing temperatures.
Loggerhead turtles nesting in terrestrial sites
Along Florida’s Atlantic Coast, the median date of egg laying for loggerhead turtles (Caretta caretta) shifted 12 days earlier over a 15-year period at what is considered to be the most important nesting beach in the western hemisphere. Researchers related this date to increased sea surface temperatures during the study period.
Plants of economic importance are vulnerable to increased frequency of ‘false springs’
Th e pattern of an early spring followed by a hard freeze (a ‘false spring’) has occurred more frequently between 1901- 2007 relative to the 1961-1990 average. Invasive plant species sustained significantly less damage to early leaf growth than native counterparts in false spring events. Damage to plants during frosts following more frequent false springs has both economic (i.e., damaged apple and peach crops) and ecological ramifications. Cascading effects can result – such as higher primary production and evaporation in streams as a consequence of increased light at the water surface from tree canopy damage sustained during the late frost. Increased primary production led to an increase in the snail population and higher rates of nitrate uptake by plants.
Over a 30-year time span (1978 to 2008) in South Carolina, researchers observed that two species of autumn-breeding amphibians arrived at breeding sites increasingly later, while two winter-breeding species arrived increasingly earlier. Th e autumn-breeding dwarf salamander (Eurycea quadridigitata) arrived as much as 76 days later. Rates of change overall ranged from 5.9 to 37.2 days per decade, and are some of the fastest rates of phenological change observed to date. Increasing overnight temperatures during the breeding season and amount of cumulative rainfall were related to the changes in arrival times. Th e authors noted that changes in breeding phenology may aff ect the outcome of competitive interactions and predator-prey dynamics.
Misconceptions about this Principle
Isn’t it true that animals and plants can adapt to changes in the climate?
The misconception goes something like this: Aren’t corals, trees, birds, mammals, and butterflies adapting well to the routine reality of changing climate? It seems like I still see the same plants and animals that I have always seen. I don’t see a sudden wave of extinctions.
The rate of climate change is so fast that most species are having trouble adapting to climate change and the impacts on many will be far-reaching and severe.
While a small percentage of species may be able to adapt to a changing climate, the science tells us that a large number of ancient mass extinction events have been strongly linked to global climate change. Because current climate change is so rapid, the way species typically adapt (for example by migrating) is, in most cases, simply not possible. Global change is too pervasive and occurring too rapidly. Read More…
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