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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's the main function of the CELL
Victor Reply
Is the smallest unit of an living things
Chanda Reply
What is a cell
Jason Reply
A cell is the basic unit of life.
Bernard
what is the photosynthesis
Brian Reply
describe cellular event during meiosis
Ruth Reply
what is reproduction
Ruth
what are the example of photosynthesis
Gamshe Reply
Is how plant covert sugar and energy, air and sunlight into energy to grow
Timileyin
An example of photosynthesis is how plants convert sugar and energy from water, air and sunlight into energy to grow.
Bernard
Pls how fertilization occurs in the womb
Rebecca
Pls am asking how does fertilization occurs in the womb
Rebecca
An egg is released in the ovary of a woman during ovulation. in the presence of a sperm this egg cell fuses with the sperm cell to form a zygote ( fertilization) this zygote now moves thru the fallopian tube down to the womb where implantation takes place. the zygote develops thru to a baby
Fru
My cordial salam to everybody. I have a question to all. What do you mean by plasma membrane?
Mahmud Reply
Plasma membrane or Cell membrane is the outer layer of tissue surrounding the whole or part of an organ. in addition, it is the outer flexible or semi-flexible covering or waterproofing whose primary function is to exclude water.(usually in plants and animals).
Job
I have a question .... Why cell wall is not present in animals cells and why it is present in plants cells?
ShAmy
what is glucose
Sisay
how alkali metal form
Puskal Reply
what is a cytosol
Siddeeqah Reply
cytosol is the internal fluid of the cell and a large part of cell were metabolism occur
Bernard
u are right dear.
Job
what is cell
Prince Reply
I think that cell is structural unit of our body. Because I have come to know that cell is the structure and biological function of an organism in the eye of scientists.
Mahmud
Cell is the fundamental, structural and functional unit of life
Winifred
Absolutely you are right. But what do you mean by life?
Mahmud
cell is the basic unit of life
Siddeeqah
life is the study of living organisms
Bernard
Cell is the basic, structural and functional unit of life. therefor no living organisms exist without a cell or a healthy cell.
Job
synthesis of 1 molecules of glucose requires
Purvesh Reply
what is the chemical composition of water
Abigail Reply
h20
Rita
h20
Asad
H20
Mathews
H2o
Bernard
H2O
Michelle
H2O
Emzzy
What is skeleton
Emzzy
skeleton is an internal or external framework of bones
Michelle
Skeleton is the structural frame work of the body
Niimat
Skeleton is the internal bony framework of the body of living organisms.
Job
Oh, how's is it going..
Brian Reply
not too good
Monique
hy
Adeola
hi
Imamkasim
hi
Veronica
Any one else taking Bio 1406 with Stephanie Martin?
Veronica
where is it ?
ShAmy
am here Veronica
iyota
Not bad
Winifred
Part of compound microscope
Bakish Reply
a. body b. stage clip c. adjacent knob d. arm e. eye piece
Kpodo
E
Rita
give five difference between worker and queen bee.
Imamkasim
How do u know when you want to urinate
Akpo Reply
how do you know when you want to urinate
Akpo
I don't know please explain
Coded
As the bladder fills up .. the signals are sent to the brain specifying that its filling up and should be emptied and the fuller it gets, the more signals/ alerts are sent to brain ...leading to the urge to urinate .... to go pee
Khalida
OK thank you
Coded
hello
Issiya
hi
Abigail
wat
Gamshe

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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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