Frequently Asked Questions - General
- What Are Some Specific Impacts on Birds?
- Can Global Warming Cause Extinctions?
- Is Wildlife Already Being Affects By Global Warming?
- How Does Global Warming Affect Birds, Other Wildlife, and Their Habitats?
- I'm Not an Energy Expert, Though. What Can I Do?
- Can Anything Be Done to Stop Global Warming?
- What Are the Likely Impacts of Global Warming if it Continues at Current Rates?
- How Do We Know Global Warming Is Really Happening?
- What Causes Global Warming?
- Couldn't Global Warming Just Be a Natural Occurance?
- Why is Global Warming a Critical Problem for All of Us?
- What is Global Warming?
Under two scenarios of global climate change, there will be major shifts in the ranges and abundances of many of the 150 common bird species in the Eastern United States over the next 100 years or so; 50-52% of species will decrease in abundance by 25% or more, while 37-40% of species will exhibit range reductions of 25% or more.
Long-distance migrants may be more vulnerable to global warming than other species. As winter temperatures increased between 1980 and 1992 at Lake Constance in Central Europe, the proportion of long-distance migrant bird species decreased while the number and proportion of residents and short-distance migrants increased. In North America, many of our favorite songbirds are long-distance migrants. Species such as Baltimore Oriole, Barn Swallow, Wood Thrush, and Scarlet Tanager could well be driven from the places where we expect to find them, more ominously, from the habitats to which they are best suited.
A 90% decline in Sooty Shearwaters (Puffinus griseus) off the California coast in just seven years (1987 -1994) has been associated with warming of the California Current, which flows from southern British Columbia to Baja California.
All of the remaining marshland in the Blackwater National Wildlife Refuge (an Important Bird Area in Maryland that provides important habitat for many birds, including Black Rail and Saltmarsh Sharp-tailed Sparrow, two of Audubon's Red WatchList species) is expected to disappear within 25 years as a result of both climate change and aquifer extraction.
Global warming and associated drought in the Prairie Potholes region (southeastern Alberta and northeastern Montana to southern Manitoba and western Minnesota) will lead to significant reductions in the populations of 14 species of migratory waterfowl; 30-50% fewer prairie ponds will hold water in spring by 2060, with an associated 40-50% decline in the numbers of ducks settling to breed in the area.
The ranges of many European and African birds are likely to shift by at least 600 miles, with a decline in species richness and reduction in average range sizes (based on simulations made for the impacts of a variety of late 21st century climate models on European and African birds).
Global warming is already causing extinctions in vulnerable species. Approximately 70 species of harlequin frogs in Central and South America have been driven to extinction by a disease that is linked with global warming. Warmer temperatures cause increased cloud cover that creates ideal conditions for a fungus that kills the frogs. This is only one cautionary example of how global warming disrupts the stability of ecosystems. As it continues, it will cause more extinctions.
Scientists predict 9-52% of all terrestrial species (1 million plants and animals) will be on an irreversible path to extinction by 2050. (These predictions are based on modeling of the effects of minimum to maximum climate warming impacts on a broad range of species in regions around the world.)
The planet's 25 biodiversity "hotspots" are especially vulnerable to climate impacts. These special places provide homes to 44% of the world's plants and 35% of its vertebrates, in less than 1.4% of its land area. A doubling of atmospheric carbon dioxide, which estimates suggest could occur in about 100 years, could lead to extinction of as many as 43% of these areas' endemic species.
There is mounting scientific evidence that global warming is already having profound effects on birds, broader biodiversity, wildlife habitat, and ecosystems. Here are some of the ways that global warming is affecting wildlife:
The ranges of many plants and animals are moving toward the poles and toward higher elevations. For example, the ranges of many British breeding birds were, on average, more than 11 miles farther north in the period from 1988-91 than they were in the period from 1968-72, according to comparisons derived from breeding bird atlases. (British butterflies are also being found farther north.)
Egg-laying, flowering, and spawning are occurring earlier for many species, in some cases disrupting delicate cycles that ensure that insects and other food are available for young animals. For example, Tree Swallows across North America have advanced egg-laying by as many as nine days from 1959 to 1991.
Migration timing and patterns
Spring migration is occurring earlier and fall migration later in many species. For example, 25 migratory bird species are arriving in Manitoba, Canada, earlier than they did 63 years ago; only two are arriving later.
Frequency and intensity of pest outbreaks
Global warming increases droughts in some areas; and spruce budworm outbreaks frequently follow droughts, perhaps because dry weather increases the stress on host trees or allows more spruce budworm eggs to be laid. Spruce budworms can be lethal to spruce trees, and spruce-fir forests are a very important habitat type in the northern hemisphere for a wide variety of plants and animals.
All organisms depend on their habitats for food, water, shelter, and opportunities to breed and raise young. Climate changes can affect organisms and their habitats in a myriad of ways. In fact, global warming impacts all life on earth, from individual organisms to populations, species, communities, and ecosystems. It can alter behaviors, population sizes, species distributions, plant and animal communities, and ecosystem functions and stability. How strongly different species will be affected varies, depending on differences in their ecology and life history. Species with small population sizes, restricted ranges, and limited ability to move to different habitat will be most at risk. Similarly, different habitats and ecosystems will be impacted differently, with those in coastal, high-latitude, and high-altitude regions most vulnerable.
When it comes to global warming, birds are like canaries in the coal mine, showing us that temperature increases are reshaping our ecology in potentially dangerous ways. According to a 2009 Audubon report, nearly 60% of 305 species found in North America in winter have been on the move over the last 40 years, shifting their ranges northward by an average of 35 miles, and in some cases by hundreds of miles.
As individuals, each of us makes countless choices each day that contribute to the amount of fossil fuels we use. We also drive the actions of corporations in our choices of consumer goods and our investment decisions. Learn how your choices can make a difference.
We can also influence policymakers with our letters, phone calls, and votes -Learn how you can get involved.
No matter what we do now, global warming will continue and will cause serious changes in our climate. However, prompt and dramatic action is likely to slow its rate of increase and to avoid some of the worst potential consequences. Experts say the most important action is to move away from burning massive amounts of fossil fuels, especially coal and oil, and to aggressively pursue nonpolluting energy options.
Every time we burn fossil fuels to drive our cars, heat our homes, run our factories, light our cities, and more, we release carbon dioxide and other greenhouse gases into the atmosphere. Our greenhouse gas emissions have increased in recent decades because of both human population growth and the rising rates of affluence and consumption. Larger houses, bigger and faster cars and SUVs and more airplane travel all mean more energy consumption. In fact, the United States, with only about 5% of the global population, contributes about 25 percent of greenhouse gas emissions because our fuel consumption is so high.
Some scientists are also studying another strategy called carbon sequestration. Earth's plants, soils, and oceans absorb huge amounts of carbon dioxide. Some scientists believe that we can augment these so-called "ecosystem services". We can protect and improve natural resources such as tropical forests that absorb large amounts of carbon. We may even be able to inject excess carbon dioxide deep into the Earth.
Most experts agree that at current rates of greenhouse gas build-up, the climate could warm by about 3.5 to 8 degrees Fahrenheit sometime after 2050, and the average global temperature might rise even higher. The expected consequences of such warming include major disruptions to agriculture, water supplies, and the diversity of life on Earth. The Greenland ice sheet could disappear in several thousand years. Hurricanes and typhoons are expected to become more intense. Precipitation is expected to increase at high latitudes and decrease in subtropical areas. Moreover, if greenhouse gases continue to build at even a moderate rate, experts predict that sea levels will be 7 to 24 inches higher by 2100, causing devastating erosion and flooding of the coastal cities and villages where millions of Earth's inhabitants live.
Over the last several decades, scientists have carefully studied patterns of climate change around the world. In its most recent assessment, the IPCC reviewed hundreds of these studies on such topics as past climate changes, observations of retreating ice, warming and rising seas, and other changes, as well as a wide array of supercomputer simulations to model how the planet has and will be affected by increasing amounts of greenhouse gases. Together these studies offer a stark portrait of a rapidly changing world:
* Temperatures have risen about 1.3 degrees F since the late 19th century. Greenhouse gas levels in the atmosphere have increased by 18% (nitrous oxide), 35% (carbon dioxide), and 148% (methane).
* Mountain glaciers and snow cover are declining in most parts of the world.
* The Greenland and Antarctic ice sheets are melting and breaking up.
* The area covered by Arctic sea ice in winter has shrunk about 2.7% each decade since 1978, with even greater summertime reductions.
* Global sea levels rose between 5 and 9 inches during the 20th century.
* The North Atlantic has shown increased hurricane intensity since 1970.
* Precipitation amounts have increased in northern Europe, the eastern Americas, and parts of Asia. Elsewhere, droughts have become longer and more severe.
- Temperatures have risen about 1.3 degrees F since the late 19th century. Greenhouse gas levels in the atmosphere have increased by 18% (nitrous oxide), 35% (carbon dioxide), and 148% (methane).
- Mountain glaciers and snow cover are declining in most parts of the world.
- The Greenland and Antarctic ice sheets are melting and breaking up.
- The area covered by Arctic sea ice in winter has shrunk about 2.7% each decade since 1978, with even greater summertime reductions.
- Global sea levels rose between 5 and 9 inches during the 20th century.
- The North Atlantic has shown increased hurricane intensity since 1970.
- Precipitation amounts have increased in northern Europe, the eastern Americas, and parts of Asia. Elsewhere, droughts have become longer and more severe.
In its February 2007 report, the Intergovernmental Panel on Climate Change, established by the World Meteorological Organization and the United Nations Environment Programme, expressed more than 90 percent confidence that global warming is caused by human activity -- namely, an increase in the amount of carbon dioxide, methane, and other heat-trapping "greenhouse" gases in the atmosphere.
Like glass in a greenhouse, these gases allow the sun's heat through the atmosphere, but then trap much of it near the Earth's surface. For billions of years they have played an important role in maintaining the proper temperatures for life to thrive. But since the Industrial Revolution, human activity has led to a dramatic increase in the amount of these heat-trapping gases. Carbon dioxide levels have risen from pre-Industrial levels of 280 parts per million to 379 parts per million. The amount of methane, another greenhouse gas, has more than doubled. The result has been a measurable warming trend called global climate change or, more specifically, global warming.
It's true that Earth's climate has always been in flux. Periods of warming have followed ice ages. A decade of warmer temperatures can be followed by a decade of cooler temperatures. But the current warming trend has been documented over a period of more than one hundred years. And it's occurring much faster than previous episodes of global warming.
Even small increases in average global temperatures can have devastating effects on people, wildlife, and the places we live. Rising temperatures in the Arctic have already reduced average ice cover, disrupting the feeding habits of polar bears and the way of life of Inuit communities. Reduced rainfall in parts of the tropics and subtropics is wreaking havoc on food production and wildlife habitat alike. Like many other organizations around the world, Audubon believes that the actions we take today can slow and eventually reverse these and other damaging patterns, protecting the quality and diversity of life on Earth for present and future generations.
Global warming is the increase in Earth's surface temperatures. Scientists say that Earth's surface temperatures rose by an estimated 1.3 degrees F in the last hundred years. In fact, eleven of the last twelve years rank among the warmest since temperatures were first recorded in the late 19th century. The chart below plots the global average temperature from the late 19th century to the year 2000.