Changes

{{for|climate change now|Global warming}}

{{for|climate change now|Global warming}}

Climate change refers to long-term changes in temperature, precipitation, and other atmospheric conditions on Earth. It primarily involves the warming of the planet due to increased concentrations of greenhouse gases, like carbon dioxide and methane, from human activities such as burning fossil fuels, deforestation, and industrial processes. These changes can lead to a variety of impacts, including more extreme weather events, rising sea levels, and disruptions to ecosystems and agriculture.  

Climate change refers to long-term changes in temperature, precipitation, and other atmospheric conditions on Earth. It primarily involves the warming of the planet due to increased concentrations of greenhouse gases, like carbon dioxide and methane, from human activities such as burning fossil fuels, deforestation, and industrial processes. These changes can lead to a variety of impacts, including more extreme weather events, rising sea levels, and disruptions to [[ecosystem]]s and agriculture.  

When people talk about climate change they are usually talking about the problem of human-caused  [[global warming]], which is happening now (see [[global warming]] for more details). But the climate of the Earth has changed over not just thousands of years, but tens or hundreds of millions of years.<ref name="Alley" />  

When people talk about climate change they are usually talking about the problem of human-caused  [[global warming]], which is happening now (see [[global warming]] for more details). But the climate of the Earth has changed over not just thousands of years, but tens or hundreds of millions of years.<ref name="Alley" />  

Sometimes, before there were people, the Earth's climate was much hotter than it is today. For example about 60 million years ago there were a lot of volcanoes, which burnt a lot of underground ''organic matter'' (squashed and [[Fossil|fossilized]] dead plants and animals became coal, gas and oil). A lot of carbon dioxide and [[methane]] went up in the air.<ref name=":1">{{Cite web|last=Lee|first=Howard|date=2020-03-19|title=Sudden Ancient Global Warming Event Traced to Magma Flood|url=https://www.quantamagazine.org/sudden-ancient-global-warming-event-traced-to-magma-flood-20200319/|access-date=2022-08-01|website=Quanta Magazine|language=en}}</ref>  

The earth's climate changes over time, so it could be hotter or colder at a certain time. For example about 60 million years ago there were a lot of volcanoes, which burnt a lot of underground ''organic matter'' (squashed and [[Fossil|fossilized]] dead plants and animals became coal, gas and oil). A lot of carbon dioxide and [[methane]] went up in the air.<ref name=":1">{{Cite web|last=Lee|first=Howard|date=2020-03-19|title=Sudden Ancient Global Warming Event Traced to Magma Flood|url=https://www.quantamagazine.org/sudden-ancient-global-warming-event-traced-to-magma-flood-20200319/|access-date=2022-08-01|website=Quanta Magazine|language=en}}</ref>  

At times in the past, the temperature was much cooler, with the last [[glaciation]] ending about ten thousand years ago.<ref name=":3">Imbrie J. & Imbrie, K.P. 1979. Ice ages: solving the mystery. Short Hills NJ: Enslow. ISBN 978-0-89490-015-0</ref><ref name=Alley>Alley R.B. 2000. ''The two-mile time machine: ice cores, abrupt climate change, and our future''. Princeton University Press. ISBN 0-691-10296-1</ref> [[Ice age|Ice Ages]] are times when the Earth got colder, and more ice froze at the [[North Pole|North]] and [[South Pole|South Poles]].<ref name=":2">{{Cite web|title=Problem Solving Activity: What Causes Ice Ages?|url=https://gml.noaa.gov/outreach/info_activities/pdfs/PSA_ice_ages.pdf}}</ref> Sometimes even the whole Earth has been covered in ice, and was much colder than today.<ref name=":4">{{cite journal | author=Williams G.E. & Schmidt P.W. | title=Paleomagnetism of the Paleoproterozoic Gowganda and Lorrain formations, Ontario: low palaeolatitude for Huronian glaciation | journal=EPSL | year=1997 | volume=153 | issue=3 | pages=157–169 | url=http://www.cosis.net/abstracts/EAE03/08262/EAE03-J-08262.pdf | doi = 10.1016/S0012-821X(97)00181-7 | bibcode=1997E&PSL.153..157W |issn=0012-821X}}</ref><ref name=":5">{{cite journal |author=Evans D.A; Beukes N.J. & Kirschvink J.L. |title=Low-latitude glaciation in the Palaeoproterozoic era |journal=Nature |volume=386 |issue=6622 |pages=262–6 |date=1997 |doi=10.1038/386262a0 |url=http://www.nature.com/nature/journal/v386/n6622/abs/386262a0.html|bibcode = 1997Natur.386..262E |s2cid=4364730 }}</ref>  

At times in the past, the temperature was much cooler, with the last [[glaciation]] ending about ten thousand years ago.<ref name=":3">Imbrie J. & Imbrie, K.P. 1979. Ice ages: solving the mystery. Short Hills NJ: Enslow. ISBN 978-0-89490-015-0</ref><ref name=Alley>Alley R.B. 2000. ''The two-mile time machine: ice cores, abrupt climate change, and our future''. Princeton University Press. ISBN 0-691-10296-1</ref> [[Ice age|Ice Ages]] are times when the Earth got colder, and more ice froze at the [[North Pole|North]] and [[South Pole|South Poles]].<ref name=":2">{{Cite web|title=Problem Solving Activity: What Causes Ice Ages?|url=https://gml.noaa.gov/outreach/info_activities/pdfs/PSA_ice_ages.pdf|access-date=2022-08-01|archive-date=2021-12-27|archive-url=https://web.archive.org/web/20211227233840/https://gml.noaa.gov/outreach/info_activities/pdfs/PSA_ice_ages.pdf|url-status=dead}}</ref> Sometimes even the whole Earth has been covered in ice, and was much colder than today.<ref name=":4">{{cite journal | author=Williams G.E. & Schmidt P.W. | title=Paleomagnetism of the Paleoproterozoic Gowganda and Lorrain formations, Ontario: low palaeolatitude for Huronian glaciation | journal=EPSL | year=1997 | volume=153 | issue=3 | pages=157–169 | url=http://www.cosis.net/abstracts/EAE03/08262/EAE03-J-08262.pdf | doi=10.1016/S0012-821X(97)00181-7 | bibcode=1997E&PSL.153..157W | issn=0012-821X | access-date=2022-08-05 | archive-date=2016-06-09 | archive-url=https://web.archive.org/web/20160609195723/http://www.cosis.net/abstracts/EAE03/08262/EAE03-J-08262.pdf | url-status=dead }}</ref><ref name=":5">{{cite journal |author=Evans D.A; Beukes N.J. & Kirschvink J.L. |title=Low-latitude glaciation in the Palaeoproterozoic era |journal=Nature |volume=386 |issue=6622 |pages=262–6 |date=1997 |doi=10.1038/386262a0 |url=http://www.nature.com/nature/journal/v386/n6622/abs/386262a0.html|bibcode = 1997Natur.386..262E |s2cid=4364730 }}</ref>  

There is no one reason why there are Ice Ages. Changes in the [[Earth's orbit]] around the Sun, and the Sun getting brighter or dimmer are events which do happen.<ref name=":2" /> Also how much the Earth is tilted compared to the Sun might make a difference.<ref name=":6">{{Cite web|title=When and how did the ice age end? Could another one start?|url=https://www.amnh.org/explore/ology/earth/ask-a-scientist-about-our-environment/how-did-the-ice-age-end}}</ref> Another source of change is the activities of living things (see [[Great Oxygenation Event]] and [[Huronian glaciation]]).<ref name=":7">{{cite journal | author=Robert E. Kopp | display-authors=etal | title=The Paleoproterozoic snowball Earth: a climate disaster triggered by the evolution of oxygenic photosynthesis | journal=Proc. Natl. Acad. Sci. U.S.A. | year=2005 | volume=102 | issue=32 | pages=11131–6 | doi=10.1073/pnas.0504878102 | pmid=16061801 | pmc=1183582 | bibcode=2005PNAS..10211131K | doi-access=free }}</ref><ref name=":8">{{cite journal|last=Lane|first=Nick|date=2010|title=First breath: Earth's billion-year struggle for oxygen|url=https://www.newscientist.com/article/mg20527461.100-first-breath-earths-billionyear-struggle-for-oxygen.html|journal=New Scientist|issue=2746|doi=}}  A snowball period, c2.4–c2.0 billion years ago, was triggered by the Great Oxygenation Event [http://ptc-cam.blogspot.com/2010/02/first-breath-earths-billion-year.html] {{Webarchive|url=https://web.archive.org/web/20110106141826/http://ptc-cam.blogspot.com/2010/02/first-breath-earths-billion-year.html|date=2011-01-06}}</ref>

There is no one reason why there are Ice Ages. Changes in the [[Earth's orbit]] around the Sun, and the Sun getting brighter or dimmer are events which do happen.<ref name=":2" /> Also how much the Earth is tilted compared to the Sun might make a difference.<ref name=":6">{{Cite web|title=When and how did the ice age end? Could another one start?|url=https://www.amnh.org/explore/ology/earth/ask-a-scientist-about-our-environment/how-did-the-ice-age-end}}</ref> Another source of change is the activities of living things (see [[Great Oxygenation Event]] and [[Huronian glaciation]]).<ref name=":7">{{cite journal | author=Robert E. Kopp | display-authors=etal | title=The Paleoproterozoic snowball Earth: a climate disaster triggered by the evolution of oxygenic photosynthesis | journal=Proc. Natl. Acad. Sci. U.S.A. | year=2005 | volume=102 | issue=32 | pages=11131–6 | doi=10.1073/pnas.0504878102 | pmid=16061801 | pmc=1183582 | bibcode=2005PNAS..10211131K | doi-access=free }}</ref><ref name=":8">{{cite journal|last=Lane|first=Nick|date=2010|title=First breath: Earth's billion-year struggle for oxygen|url=https://www.newscientist.com/article/mg20527461.100-first-breath-earths-billionyear-struggle-for-oxygen.html|journal=New Scientist|issue=2746|doi=}}  A snowball period, c2.4–c2.0 billion years ago, was triggered by the Great Oxygenation Event [http://ptc-cam.blogspot.com/2010/02/first-breath-earths-billion-year.html] {{Webarchive|url=https://web.archive.org/web/20110106141826/http://ptc-cam.blogspot.com/2010/02/first-breath-earths-billion-year.html|date=2011-01-06}}</ref>

== Hot Earth ==

== Hot Earth ==

Sometimes, before there were people, the Earth's climate was much hotter than it is today. For example about 60 million years ago there were a lot of volcanoes, which burnt a lot of underground ''organic matter'' (squashed and [[Fossil|fossilized]] dead plants and animals like coal, gas and oil)  so a lot of carbon dioxide and [[methane]] went up in the air like nowadays.<ref name=":1" /> This made the Earth hot enough for giant [[Tortoise|tortoises]] and [[Alligator|alligators]] to live in the [[Arctic]].<ref name=":1" />

Sometimes, before there were people, the Earth's climate was much hotter than it is today. For example about 60 million years ago there were a lot of volcanoes, which burnt a lot of underground ''organic matter'' (squashed and [[Fossil|fossilized]] dead plants and animals like coal, gas and oil)  so a lot of carbon dioxide and [[methane]] went up in the air like nowadays.<ref name=":1" /> This made the Earth hot enough for giant [[Tortoise|tortoises]] and [[Alligator|alligators]] to live in the [[Arctic]].<ref name=":1" />

At times in the past, the temperature was much cooler, with the last [[glaciation]] ending about ten thousand years ago.<ref name=":3" /><ref name="Alley" />

At times in the past, the temperature was much cooler, with the last [[glaciation]] ending about ten thousand years ago.<ref name=":3" /><ref name="Alley" />

== Ice Ages ==

== Ice Ages ==

[[Ice age|Ice Ages]] are long times (much much longer than glaciations) when the Earth got colder, and more ice froze at the [[North Pole|North]] and [[South Pole|South Poles]].<ref name=":2" /> Sometimes even the whole Earth was covered in ice, and was much colder than today.<ref name=":4" /><ref name=":5" /> There is no one reason why there are Ice Ages. Changes in the [[Earth's orbit]] around the Sun, and the Sun getting brighter or dimmer are events which do happen.<ref name=":2" /> Also how much the Earth is tilted compared to the Sun might make a difference.<ref name=":6" /> Another source of change is the activities of living things (see [[Great Oxygenation Event]] and [[Huronian glaciation]]).<ref name=":7" /><ref name=":8" />

[[Ice age|Ice Ages]] are long times (much much longer than glaciations) when the Earth got colder, and more ice froze at the [[North Pole|North]] and [[South Pole|South Poles]].<ref name=":2" /> Sometimes even the whole Earth was covered in ice, and was much colder than today.<ref name=":4" /><ref name=":5" /> There is no one reason why there are Ice Ages. Changes in the [[Earth's orbit]] around the Sun, and the Sun getting brighter or dimmer are events which do happen.<ref name=":2" /> Also how much the Earth is tilted compared to the Sun might make a difference.<ref name=":6" /> Another source of change is the activities of living things (see [[Great Oxygenation Event]] and [[Huronian glaciation|Huronia glaciation]]).<ref name=":7" /><ref name=":8" />

== History of climate change studies ==

== History of climate change studies ==

[[Joseph Fourier]] in 1824, Claude Pouillet in 1827 and 1838, Eunice Foote (1819{{ndash}}1888) in 1856, Irish physicist [[John Tyndall]] (1820–1893) in 1863 onwards,<ref>Tyndall J. 1863. ''Heat as a mode of motion''. London & New York.</ref> [[Svante Arrhenius]] in 1896, and Guy Stewart Callendar (1898–1964) discovered the importance of [[carbon dioxide]] (CO₂) in climate change. Foote's work was not appreciated, and not widely known. Tyndall proved there were other greenhouse gases as well. [[Nils Gustaf Ekholm]] in 1901 invented the term.<ref>{{cite web|last1=Easterbrook|first1=Steve|title=Who first coined the term "Greenhouse Effect"?|url=http://www.easterbrook.ca/steve/2015/08/who-first-coined-the-term-greenhouse-effect/|website=Serendipity|date=18 August 2015 |accessdate=11 November 2015}}</ref><ref>{{cite journal |author=Ekholm N |doi=10.1002/qj.49702711702 |title=On the variations of the climate of the geological and historical past and their causes |journal=Quarterly Journal of the Royal Meteorological Society |volume=27 |number=117 |pages=1–62 |year=1901|bibcode=1901QJRMS..27....1E }}</ref>

[[Joseph Fourier]] in 1824, Claude Pouillet in 1827 and 1838, Eunice Foote (1819{{ndash}}1888) in 1856, Irish physicist [[John Tyndall]] (1820–1893) in 1863 onwards,<ref>Tyndall J. 1863. ''Heat as a mode of motion''. London & New York.</ref> [[Svante Arrhenius]] in 1896, and Guy Stewart Calendar (1898–1964) discovered the importance of [[carbon dioxide]] (CO₂) in climate change. Foote's work was not appreciated, and not widely known. Tyndall proved there were other greenhouse gases as well. [[Nils Gustaf Ekholm]] in 1901 invented the term.<ref>{{cite web|last1=Easterbrook|first1=Steve|title=Who first coined the term "Greenhouse Effect"?|url=http://www.easterbrook.ca/steve/2015/08/who-first-coined-the-term-greenhouse-effect/|website=Serendipity|date=18 August 2015 |accessdate=11 November 2015}}</ref><ref>{{cite journal |author=Ekholm N |doi=10.1002/qj.49702711702 |title=On the variations of the climate of the geological and historical past and their causes |journal=Quarterly Journal of the Royal Meteorological Society |volume=27 |number=117 |pages=1–62 |year=1901|bibcode=1901QJRMS..27....1E }}</ref>

== The Sun ==

== The Sun ==

The [[Sun]] gets a little bit hotter and colder every 11 years. This is called the 11-year [[sunspot]] cycle. The change is so small that scientists can barely measure how it affects the temperature of the Earth. If the Sun was causing the Earth to warm up, it would warm both the surface and high up in the air. But the air in the upper [[stratosphere]] is actually getting colder. Therefore the changes in the Sun are not causing the [[global warming]] which is happening now.

The [[Sun]] gets a little bit hotter and colder every 11 years. This is called the 11-year [[sunspot]] cycle. The change is so small that scientists can barely measure how it affects the temperature of the Earth. If the Sun was causing the Earth to warm up, it would warm both the surface and high up in the air. But the air in the upper [[stratosphere]] is actually getting colder. Therefore the changes in the Sun are not causing the [[global warming]] which is happening now.

According to the United Nations’ Intergovernmental Panel on Climate Change (IPCC), the current scientific consensus is that long and short-term variations in solar activity play only a very small role in Earth’s climate. Warming from increased levels of human-produced greenhouse gases is actually many times stronger than any effects due to recent variations in solar activity.

According to the United Nations’ [[Intergovernmental Panel on Climate Change]] (IPCC), the current scientific consensus is that long and short-term variations in solar activity play only a very small role in Earth’s climate. Warming from increased levels of human-produced greenhouse gases is actually many times stronger than any effects due to recent variations in solar activity.

For more than 40 years, satellites have observed the Sun's energy output, which has gone up or down by less than 0.1 percent during that period. Since 1750, the warming driven by greenhouse gases coming from the human burning of fossil fuels is over 270 times greater than the slight extra warming coming from the Sun itself over that same time .[https://climate.nasa.gov/explore/ask-nasa-climate/2910/what-is-the-suns-role-in-climate-change/]

For more than 40 years, satellites have observed the Sun's energy output, which has gone up or down by less than 0.1 percent during that period. Since 1750, the warming driven by greenhouse gases coming from the human burning of fossil fuels is over 270 times greater than the slight extra warming coming from the Sun itself over that same time .[https://climate.nasa.gov/explore/ask-nasa-climate/2910/what-is-the-suns-role-in-climate-change/]

== Sustainable energy and environment ==

== Sustainable energy and environment ==

Renewable energy or sustainable energy includes any energy source that cannot be exhausted. It can remain viable for a long period of time without running out or lasts forever. Examples are solar, wind, hydropower (water), geothermal, tidal and biomass.<ref>{{Cite web|title=What is Sustainable Energy and Why Do We Need It?|url=https://www.routledge.com/blog/article/what-is-sustainable-energy-and-why-do-we-need-it#|access-date=2023-08-19|website=www.routledge.com}}</ref><ref name=":9">{{Cite web|title=Types of renewable energy|url=https://www.edfenergy.com/energywise/renewable-energy-sources|access-date=2023-08-19|website=EDF|language=en}}</ref>  

[[Renewable energy]] or sustainable energy includes any energy source that cannot be exhausted. It can remain viable for a long period of time without running out or lasts forever. Examples are solar, wind, hydropower (water), geothermal, tidal and biomass.<ref>{{Cite web|title=What is Sustainable Energy and Why Do We Need It?|url=https://www.routledge.com/blog/article/what-is-sustainable-energy-and-why-do-we-need-it#|access-date=2023-08-19|website=www.routledge.com}}</ref><ref name=":9">{{Cite web|title=Types of renewable energy|url=https://www.edfenergy.com/energywise/renewable-energy-sources|access-date=2023-08-19|website=EDF|language=en}}</ref>  

Sustainable energy choices play a crucial role in mitigating the impact of human activities on the environment. Here's an overview of some key sustainable energy options and their environmental impacts according to research:

Sustainable energy choices play a crucial role in mitigating the impact of human activities on the environment. Here's an overview of some key sustainable energy options and their environmental impacts according to research:

File:Change in Average Temperature With Fahrenheit.svg|Changes in [[surface air temperature]] over the past 50 years. The [[Arctic]] has warmed the most, and temperatures on land have generally increased more than [[sea surface temperature]]s.

File:Change in Average Temperature With Fahrenheit.svg|Changes in [[surface air temperature]] over the past 50 years. The [[Arctic]] has warmed the most, and temperatures on land have generally increased more than [[sea surface temperature]]s.

File:Global Temperature And Forces With Fahrenheit.svg|Earth's average surface air temperature has increased almost 1.5{{nbsp}}°C (about{{nbsp}}2.5 °F) since the [[Industrial Revolution]]. Natural forces cause some variability, but the 20-year average shows the progressive influence of human activity.

File:Global Temperature And Forces With Fahrenheit.svg|Earth's average surface air temperature has increased almost 1.5{{nbsp}}°C (about{{nbsp}}2.5&nbsp;°F) since the [[Industrial Revolution]]. Natural forces cause some variability, but the 20-year average shows the progressive influence of human activity.

File:Common Era Temperature.svg|[[Global surface temperature]] reconstruction over the last 2000 years using proxy data from tree rings, corals, and ice cores in blue. Directly observed data is in red.

File:Common Era Temperature.svg|[[Global surface temperature]] reconstruction over the last 2000 years using proxy data from tree rings, corals, and ice cores in blue. Directly observed data is in red.

File:1955- Ocean heat content - NOAA.svg|There has been an increase in [[ocean heat content]] during recent decades as the oceans absorb over 90% of the [[Earth's energy budget|heat from global warming]].

File:1955- Ocean heat content - NOAA.svg|There has been an increase in [[ocean heat content]] during recent decades as the oceans absorb over 90% of the [[Earth's energy budget|heat from global warming]].

File:Projected Change in Temperatures by 2090.svg|[[Coupled Model Intercomparison Project#CMIP Phase 6|CMIP6]] multi-model projections of [[global surface temperature]] changes for the year 2090 relative to the 1850–1900 average. The current trajectory for warming by the end of the century is roughly halfway between these two extremes.

File:Projected Change in Temperatures by 2090.svg|[[Coupled Model Intercomparison Project#CMIP Phase 6|CMIP6]] multi-model projections of [[global surface temperature]] changes for the year 2090 relative to the 1850–1900 average. The current trajectory for warming by the end of the century is roughly halfway between these two extremes.

File:CO2 Emissions by Source Since 1880.svg|The [[Global Carbon Project]] shows how additions to {{CO2}} since 1880 have been caused by different sources ramping up one after another.

File:CO2 Emissions by Source Since 1880.svg|The [[Global Carbon Project]] shows how additions to {{CO2}} since 1880 have been caused by different sources ramping up one after another.

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== Related pages ==

== Related pages ==

*[[Ecology]]

*[[Ecology]]

*[[Intergovernmental Panel on Climate Change]]

*[[Intergovernmental Panel on Climate Change]]

== References. ==

== References. ==

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