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 This photo shows a smokestack from a factory churning gray smoke into the air.
The burning of fossil fuels in industry and by vehicles releases carbon dioxide and other greenhouse gases into the atmosphere. (credit: “Pöllö”/Wikimedia Commons)

Documented results of climate change: past and present

Scientists have geological evidence of the consequences of long-ago climate change. Modern-day phenomena such as retreating glaciers and melting polar ice cause a continual rise in sea level. Meanwhile, changes in climate can negatively affect organisms.

Geological climate change

Global warming has been associated with at least one planet-wide extinction event during the geological past. The Permian extinction event occurred about 251 million years ago toward the end of the roughly 50-million-year-long geological time span known as the Permian period. This geologic time period was one of the three warmest periods in Earth’s geologic history. Scientists estimate that approximately 70 percent of the terrestrial plant and animal species and 84 percent of marine species became extinct, vanishing forever near the end of the Permian period. Organisms that had adapted to wet and warm climatic conditions, such as annual rainfall of 300–400 cm (118–157 in) and 20 °C–30 °C (68 °F–86 °F) in the tropical wet forest, may not have been able to survive the Permian climate change.

Watch this NASA video to discover the mixed effects of global warming on plant growth. While scientists found that warmer temperatures in the 1980s and 1990s caused an increase in plant productivity, this advantage has since been counteracted by more frequent droughts.

Present climate change

A number of global events have occurred that may be attributed to climate change during our lifetimes. Glacier National Park in Montana is undergoing the retreat of many of its glaciers, a phenomenon known as glacier recession. In 1850, the area contained approximately 150 glaciers. By 2010, however, the park contained only about 24 glaciers greater than 25 acres in size. One of these glaciers is the Grinnell Glacier ( [link] ) at Mount Gould. Between 1966 and 2005, the size of Grinnell Glacier shrank by 40 percent. Similarly, the mass of the ice sheets in Greenland and the Antarctic is decreasing: Greenland lost 150–250 km 3 of ice per year between 2002 and 2006. In addition, the size and thickness of the Arctic sea ice is decreasing.

 A series of photos shows the Grinnel Glacier in 1938, 1981, 1998 and 2009. In 1938, the lake beneath the glacier was completely frozen. In 1981, about one-third of the lake was thawed. In 1998, two-thirds of the lake was thawed. In 2009, it was covered with chunks of ice, but otherwise it was completely thawed. At the same time, the glacier itself has steadily receded.
The effect of global warming can be seen in the continuing retreat of Grinnel Glacier. The mean annual temperature in the park has increased 1.33 °C since 1900. The loss of a glacier results in the loss of summer meltwaters, sharply reducing seasonal water supplies and severely affecting local ecosystems. (credit: modification of work by USGS)

This loss of ice is leading to increases in the global sea level. On average, the sea is rising at a rate of 1.8 mm per year. However, between 1993 and 2010 the rate of sea level increase ranged between 2.9 and 3.4 mm per year. A variety of factors affect the volume of water in the ocean, including the temperature of the water (the density of water is related to its temperature) and the amount of water found in rivers, lakes, glaciers, polar ice caps, and sea ice. As glaciers and polar ice caps melt, there is a significant contribution of liquid water that was previously frozen.

In addition to some abiotic conditions changing in response to climate change, many organisms are also being affected by the changes in temperature. Temperature and precipitation play key roles in determining the geographic distribution and phenology of plants and animals. (Phenology is the study of the effects of climatic conditions on the timing of periodic lifecycle events, such as flowering in plants or migration in birds.) Researchers have shown that 385 plant species in Great Britain are flowering 4.5 days sooner than was recorded earlier during the previous 40 years. In addition, insect-pollinated species were more likely to flower earlier than wind-pollinated species. The impact of changes in flowering date would be mitigated if the insect pollinators emerged earlier. This mismatched timing of plants and pollinators could result in injurious ecosystem effects because, for continued survival, insect-pollinated plants must flower when their pollinators are present.

Section summary

The Earth has gone through periodic cycles of increases and decreases in temperature. During the past 2000 years, the Medieval Climate Anomaly was a warmer period, while the Little Ice Age was unusually cool. Both of these irregularities can be explained by natural causes of changes in climate, and, although the temperature changes were small, they had significant effects. Natural drivers of climate change include Milankovitch cycles, changes in solar activity, and volcanic eruptions. None of these factors, however, leads to rapid increases in global temperature or sustained increases in carbon dioxide. The burning of fossil fuels is an important source of greenhouse gases, which plays a major role in the greenhouse effect. Long ago, global warming resulted in the Permian extinction: a large-scale extinction event that is documented in the fossil record. Currently, modern-day climate change is associated with the increased melting of glaciers and polar ice sheets, resulting in a gradual increase in sea level. Plants and animals can also be affected by global climate change when the timing of seasonal events, such as flowering or pollination, is affected by global warming.

Questions & Answers

what is the protein found in the blood?
Tobias Reply
globin
Joelia
Globin
globulins
EZRA
globulins
SASMITA
what is parasitic movement
Emmanuel Reply
Parasitic movement is a problem for all of us. So is its companion, parasitic tension. Parasitic movement is the excess contraction of muscles that you don't actually need to complete an action.
freya
what are eukaryotic cells
Thiza Reply
eukaryotic cells which posses a true nucleus that is the DNA is enclosed and covered by a nuclear membrane
Grace
what is the mean of pair of chromosomes
Kazula Reply
hi
Lagos
23 haploid and 23diploid
Patson
how are you studying in this quarantine? .. how are you keeping yourselves motivated?
sivajijadhav @815.com
good morning guyz
Joelia
morning
Kazula
hi
Justin
Good
Angela
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Angela
what is the important of sex
Aremu Reply
why did human being need sex?
Aremu
because he/she have feelings
Chripine
reproduction...to make more
Yazi
due to active harmon
Manish
One important of sex is to reproduce
Emma
to ensure the countinuty of life
Yusuf
all of you are right
Edith
what is momentum
Asiya Reply
The strength or force that allows something to continue or grow stronger or faster as time pass
Emma
What is Centripetal Force?
Justin
centrepital force is the inward force required to keep a body moving with constant speed in a circular path
Yusuf
what is the test for protein
Takii Reply
List four condition necessary for seed germination
Tedeka Reply
water,air(oxygen),light,temperature
Hassan
water, light, oxygen and temperature
lilchris
water, oxygen, light temperature
Mike
water oxygen light and temperature
John
importance of biology
Alabina Reply
importance of boilogy
Alabina
what is soil
Amina Reply
soil is the upper part of the earth
Alabina
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Alabina
soil is the uppermost layer of the earth on which plant grows
Yusuf
soil is defined as the thin surface of the upper most layer of the earth crust on which plants grow
Thanni
soil is the upper part of the earth which plants grow on
Emma
differences between euglenoid and amoeboid
Grace Reply
what are the difference between aerobic and anaerobic respiration?
Maxwell Reply
Aerobic respiration involves the use of oxygen whiles anaerobic respiration does not involve the use of oxygen
Quabena
what is assmilation
Lucy Reply
what is cell
Manish Reply
cell is the structural and functional unit of life or living things
hamid
where anaerobic respiration occurre?
Manish
in cell
Manish
in cells?
Manish
where anaerobic respiration occurre in cell?
Manish

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Source:  OpenStax, Biology. OpenStax CNX. Feb 29, 2016 Download for free at http://cnx.org/content/col11448/1.10
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