{"id":3370,"date":"2017-02-14T20:17:27","date_gmt":"2017-02-14T20:17:27","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/wm-biology2\/?post_type=chapter&#038;p=3370"},"modified":"2024-04-26T02:47:27","modified_gmt":"2024-04-26T02:47:27","slug":"drivers-of-global-climate-change","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/wm-biology2\/chapter\/drivers-of-global-climate-change\/","title":{"raw":"Drivers of Global Climate Change","rendered":"Drivers of Global Climate Change"},"content":{"raw":"<div class=\"textbox learning-objectives\">\r\n<h3>Learning Outcomes<\/h3>\r\n<ul>\r\n \t<li>Identify different drivers of global climate change<\/li>\r\n<\/ul>\r\n<\/div>\r\n<p id=\"fs-idp18745344\">Because it is not possible to go back in time to directly observe and measure climate, scientists must use\u00a0<em data-effect=\"italics\">indirect evidence<\/em>\u00a0to determine the\u00a0<em data-effect=\"italics\">drivers<\/em>, or factors, that may be responsible for climate change. The indirect evidence includes data collected using ice cores,\u00a0<em data-effect=\"italics\">boreholes<\/em>\u00a0(a narrow shaft bored into the ground), tree rings, glacier lengths, pollen remains, and ocean sediments. The data shows a correlation between the timing of temperature changes and drivers of climate change. Before the Industrial Era (pre-1780), there were three drivers of climate change that were not related to human activity or atmospheric gases. The first of these is the\u00a0<em data-effect=\"italics\">Milankovitch cycles<\/em>. The\u00a0<strong><span id=\"term2254\" data-type=\"term\">Milankovitch cycles<\/span><\/strong>\u00a0describe the effects of slight changes in the Earth\u2019s orbit on Earth\u2019s climate. The length of the Milankovitch cycles ranges between 19,000 and 100,000 years. In other words, one could expect to see some predictable changes in the Earth\u2019s climate associated with changes in the Earth\u2019s orbit at a minimum of every 19,000 years.<\/p>\r\n<p id=\"fs-idp130660256\">The\u00a0<em data-effect=\"italics\">variation in the sun\u2019s intensity<\/em>\u00a0is the second natural factor responsible for climate change.\u00a0<span id=\"term2255\" data-type=\"term\">Solar intensity<\/span>\u00a0is the amount of solar power or energy the sun emits in a given amount of time. There is a direct relationship between solar intensity and temperature. As solar intensity increases (or decreases), the Earth\u2019s temperature correspondingly increases (or decreases). Changes in solar intensity have been proposed as one of several possible explanations for the Little Ice Age.<\/p>\r\n<p id=\"fs-idp64728608\">Finally,\u00a0<em data-effect=\"italics\">volcanic eruptions<\/em>\u00a0are a third natural driver of climate change. Volcanic eruptions can last a few days, but the solids and gases released during an eruption can influence the climate over a period of a few years, causing short-term climate changes. The gases and solids released by volcanic eruptions can include carbon dioxide, water vapor, sulfur dioxide, hydrogen sulfide, hydrogen, and carbon monoxide. Generally, volcanic eruptions cool the climate. This occurred in 1783 when volcanos in Iceland erupted and caused the release of large volumes of sulfuric oxide. This led to\u00a0<strong><span id=\"term2256\" data-type=\"term\">haze-effect cooling<\/span><\/strong>, a global phenomenon that occurs when dust, ash, or other suspended particles block out sunlight and trigger lower global temperatures as a result; haze-effect cooling usually extends for one or more years before dissipating in intensity. In Europe and North America, haze-effect cooling produced some of the lowest average winter temperatures on record in 1783 and 1784.<\/p>\r\n<p id=\"fs-idp47789312\"><em data-effect=\"italics\">Greenhouse gases<\/em>\u00a0are probably the most significant drivers of the climate. When heat energy from the sun strikes the Earth, gases known as\u00a0<strong><span id=\"term2257\" data-type=\"term\">greenhouse gases<\/span><\/strong>\u00a0trap the heat in the atmosphere, in a similar manner as do the glass panes of a greenhouse keep heat from escaping. The greenhouse gases that affect Earth include carbon dioxide, methane, water vapor, nitrous oxide, and ozone. Approximately half of the radiation from the sun passes through these gases in the atmosphere and strikes the Earth. This radiation is converted into thermal (infrared) radiation on the Earth\u2019s surface, and then a portion of that energy is re-radiated back into the atmosphere. Greenhouse gases, however, reflect much of the thermal energy back to the Earth\u2019s surface. The more greenhouse gases there are in the atmosphere, the more thermal energy is reflected back to the Earth\u2019s surface, heating it up and the atmosphere immediately above it. Greenhouse gases absorb and emit radiation and are an important factor in the\u00a0<strong><span id=\"term2258\" data-type=\"term\">greenhouse effect<\/span><\/strong>: the warming of Earth due to carbon dioxide and other greenhouse gases in the atmosphere.<\/p>\r\n<p id=\"fs-idp85306768\">Direct evidence supports the relationship between atmospheric concentrations of carbon dioxide and temperature: as carbon dioxide rises, global temperature rises. Since 1950, the concentration of atmospheric carbon dioxide has increased from about 280 ppm to 382 ppm in 2006. In 2011, the atmospheric carbon dioxide concentration was 392 ppm. However, the planet would not be inhabitable by current life forms if water vapor did not produce its drastic greenhouse warming effect.<\/p>\r\n<p id=\"fs-idp64620832\">Scientists look at patterns in data and try to explain differences or deviations from these patterns. The atmospheric carbon dioxide data reveal a historical pattern of carbon dioxide increasing and decreasing, cycling between a low of 180 ppm and a high of 300 ppm. Scientists have concluded that it took around 50,000 years for the atmospheric carbon dioxide level to increase from its low minimum concentration to its higher maximum concentration. However, beginning only a few centuries ago, atmospheric carbon dioxide concentrations have increased beyond the historical maximum of 300 ppm. The current increases in atmospheric carbon dioxide have happened very quickly\u2014in a matter of hundreds of years rather than thousands of years. What is the reason for this difference in the rate of change and the amount of increase in carbon dioxide? A key factor that must be recognized when comparing the historical data and the current data is the presence and industrial activities of modern human society; no other driver of climate change has yielded changes in atmospheric carbon dioxide levels\u00a0<em data-effect=\"italics\">at this rate or to this magnitude<\/em>.<\/p>\r\n\r\n\r\n[caption id=\"attachment_3376\" align=\"alignright\" width=\"300\"]<img class=\"wp-image-3376\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/02\/14201629\/Figure_44_05_03.jpg\" alt=\" This photo shows a smokestack from a factory churning gray smoke into the air.\" width=\"300\" height=\"402\" \/> Figure 1. The burning of fossil fuels in industry and by vehicles releases carbon dioxide and other greenhouse gases into the atmosphere. (credit: \u201cP\u00f6ll\u00f6\u201d\/Wikimedia Commons)[\/caption]\r\n<p id=\"fs-idp17519264\">Human activity releases carbon dioxide and methane, two of the most important greenhouse gases, into the atmosphere in several ways. The primary mechanism that releases carbon dioxide is the burning of fossil fuels, such as gasoline, coal, and natural gas (Figure 1).<\/p>\r\nDeforestation, cement manufacture, animal agriculture, the clearing of land, and the burning of forests are other human activities that release carbon dioxide. Methane (CH<sub>4<\/sub>) is produced when bacteria break down organic matter under anaerobic conditions. Anaerobic conditions can happen when organic matter is trapped underwater (such as in rice paddies) or in the intestines of herbivores. Methane can also be released from natural gas fields and the decomposition of animal and plant material that occurs in landfills. Another source of methane is the melting of\u00a0<em data-effect=\"italics\">clathrates<\/em>.\r\n\r\n<strong><span id=\"term2259\" data-type=\"term\">Clathrates<\/span><\/strong>\u00a0are frozen chunks of ice and methane found at the bottom of the ocean. When water warms, these chunks of ice melt and methane is released. As the ocean\u2019s water temperature increases, the rate at which clathrates melt is increasing, releasing even more methane. This leads to increased levels of methane in the atmosphere, which further accelerates the rate of global warming. This is an example of the positive feedback loop that is leading to the rapid rate of increase of global temperatures.\r\n<div class=\"textbox tryit\">\r\n<h3>Try It<\/h3>\r\nhttps:\/\/assess.lumenlearning.com\/practice\/0d51705d-8a79-4852-b3b7-9461f0d8a2c3\r\n<\/div>","rendered":"<div class=\"textbox learning-objectives\">\n<h3>Learning Outcomes<\/h3>\n<ul>\n<li>Identify different drivers of global climate change<\/li>\n<\/ul>\n<\/div>\n<p id=\"fs-idp18745344\">Because it is not possible to go back in time to directly observe and measure climate, scientists must use\u00a0<em data-effect=\"italics\">indirect evidence<\/em>\u00a0to determine the\u00a0<em data-effect=\"italics\">drivers<\/em>, or factors, that may be responsible for climate change. The indirect evidence includes data collected using ice cores,\u00a0<em data-effect=\"italics\">boreholes<\/em>\u00a0(a narrow shaft bored into the ground), tree rings, glacier lengths, pollen remains, and ocean sediments. The data shows a correlation between the timing of temperature changes and drivers of climate change. Before the Industrial Era (pre-1780), there were three drivers of climate change that were not related to human activity or atmospheric gases. The first of these is the\u00a0<em data-effect=\"italics\">Milankovitch cycles<\/em>. The\u00a0<strong><span id=\"term2254\" data-type=\"term\">Milankovitch cycles<\/span><\/strong>\u00a0describe the effects of slight changes in the Earth\u2019s orbit on Earth\u2019s climate. The length of the Milankovitch cycles ranges between 19,000 and 100,000 years. In other words, one could expect to see some predictable changes in the Earth\u2019s climate associated with changes in the Earth\u2019s orbit at a minimum of every 19,000 years.<\/p>\n<p id=\"fs-idp130660256\">The\u00a0<em data-effect=\"italics\">variation in the sun\u2019s intensity<\/em>\u00a0is the second natural factor responsible for climate change.\u00a0<span id=\"term2255\" data-type=\"term\">Solar intensity<\/span>\u00a0is the amount of solar power or energy the sun emits in a given amount of time. There is a direct relationship between solar intensity and temperature. As solar intensity increases (or decreases), the Earth\u2019s temperature correspondingly increases (or decreases). Changes in solar intensity have been proposed as one of several possible explanations for the Little Ice Age.<\/p>\n<p id=\"fs-idp64728608\">Finally,\u00a0<em data-effect=\"italics\">volcanic eruptions<\/em>\u00a0are a third natural driver of climate change. Volcanic eruptions can last a few days, but the solids and gases released during an eruption can influence the climate over a period of a few years, causing short-term climate changes. The gases and solids released by volcanic eruptions can include carbon dioxide, water vapor, sulfur dioxide, hydrogen sulfide, hydrogen, and carbon monoxide. Generally, volcanic eruptions cool the climate. This occurred in 1783 when volcanos in Iceland erupted and caused the release of large volumes of sulfuric oxide. This led to\u00a0<strong><span id=\"term2256\" data-type=\"term\">haze-effect cooling<\/span><\/strong>, a global phenomenon that occurs when dust, ash, or other suspended particles block out sunlight and trigger lower global temperatures as a result; haze-effect cooling usually extends for one or more years before dissipating in intensity. In Europe and North America, haze-effect cooling produced some of the lowest average winter temperatures on record in 1783 and 1784.<\/p>\n<p id=\"fs-idp47789312\"><em data-effect=\"italics\">Greenhouse gases<\/em>\u00a0are probably the most significant drivers of the climate. When heat energy from the sun strikes the Earth, gases known as\u00a0<strong><span id=\"term2257\" data-type=\"term\">greenhouse gases<\/span><\/strong>\u00a0trap the heat in the atmosphere, in a similar manner as do the glass panes of a greenhouse keep heat from escaping. The greenhouse gases that affect Earth include carbon dioxide, methane, water vapor, nitrous oxide, and ozone. Approximately half of the radiation from the sun passes through these gases in the atmosphere and strikes the Earth. This radiation is converted into thermal (infrared) radiation on the Earth\u2019s surface, and then a portion of that energy is re-radiated back into the atmosphere. Greenhouse gases, however, reflect much of the thermal energy back to the Earth\u2019s surface. The more greenhouse gases there are in the atmosphere, the more thermal energy is reflected back to the Earth\u2019s surface, heating it up and the atmosphere immediately above it. Greenhouse gases absorb and emit radiation and are an important factor in the\u00a0<strong><span id=\"term2258\" data-type=\"term\">greenhouse effect<\/span><\/strong>: the warming of Earth due to carbon dioxide and other greenhouse gases in the atmosphere.<\/p>\n<p id=\"fs-idp85306768\">Direct evidence supports the relationship between atmospheric concentrations of carbon dioxide and temperature: as carbon dioxide rises, global temperature rises. Since 1950, the concentration of atmospheric carbon dioxide has increased from about 280 ppm to 382 ppm in 2006. In 2011, the atmospheric carbon dioxide concentration was 392 ppm. However, the planet would not be inhabitable by current life forms if water vapor did not produce its drastic greenhouse warming effect.<\/p>\n<p id=\"fs-idp64620832\">Scientists look at patterns in data and try to explain differences or deviations from these patterns. The atmospheric carbon dioxide data reveal a historical pattern of carbon dioxide increasing and decreasing, cycling between a low of 180 ppm and a high of 300 ppm. Scientists have concluded that it took around 50,000 years for the atmospheric carbon dioxide level to increase from its low minimum concentration to its higher maximum concentration. However, beginning only a few centuries ago, atmospheric carbon dioxide concentrations have increased beyond the historical maximum of 300 ppm. The current increases in atmospheric carbon dioxide have happened very quickly\u2014in a matter of hundreds of years rather than thousands of years. What is the reason for this difference in the rate of change and the amount of increase in carbon dioxide? A key factor that must be recognized when comparing the historical data and the current data is the presence and industrial activities of modern human society; no other driver of climate change has yielded changes in atmospheric carbon dioxide levels\u00a0<em data-effect=\"italics\">at this rate or to this magnitude<\/em>.<\/p>\n<div id=\"attachment_3376\" style=\"width: 310px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-3376\" class=\"wp-image-3376\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/02\/14201629\/Figure_44_05_03.jpg\" alt=\"This photo shows a smokestack from a factory churning gray smoke into the air.\" width=\"300\" height=\"402\" \/><\/p>\n<p id=\"caption-attachment-3376\" class=\"wp-caption-text\">Figure 1. The burning of fossil fuels in industry and by vehicles releases carbon dioxide and other greenhouse gases into the atmosphere. (credit: \u201cP\u00f6ll\u00f6\u201d\/Wikimedia Commons)<\/p>\n<\/div>\n<p id=\"fs-idp17519264\">Human activity releases carbon dioxide and methane, two of the most important greenhouse gases, into the atmosphere in several ways. The primary mechanism that releases carbon dioxide is the burning of fossil fuels, such as gasoline, coal, and natural gas (Figure 1).<\/p>\n<p>Deforestation, cement manufacture, animal agriculture, the clearing of land, and the burning of forests are other human activities that release carbon dioxide. Methane (CH<sub>4<\/sub>) is produced when bacteria break down organic matter under anaerobic conditions. Anaerobic conditions can happen when organic matter is trapped underwater (such as in rice paddies) or in the intestines of herbivores. Methane can also be released from natural gas fields and the decomposition of animal and plant material that occurs in landfills. Another source of methane is the melting of\u00a0<em data-effect=\"italics\">clathrates<\/em>.<\/p>\n<p><strong><span id=\"term2259\" data-type=\"term\">Clathrates<\/span><\/strong>\u00a0are frozen chunks of ice and methane found at the bottom of the ocean. When water warms, these chunks of ice melt and methane is released. As the ocean\u2019s water temperature increases, the rate at which clathrates melt is increasing, releasing even more methane. This leads to increased levels of methane in the atmosphere, which further accelerates the rate of global warming. This is an example of the positive feedback loop that is leading to the rapid rate of increase of global temperatures.<\/p>\n<div class=\"textbox tryit\">\n<h3>Try It<\/h3>\n<p>\t<iframe id=\"assessment_practice_0d51705d-8a79-4852-b3b7-9461f0d8a2c3\" class=\"resizable\" src=\"https:\/\/assess.lumenlearning.com\/practice\/0d51705d-8a79-4852-b3b7-9461f0d8a2c3?iframe_resize_id=assessment_practice_id_0d51705d-8a79-4852-b3b7-9461f0d8a2c3\" frameborder=\"0\" style=\"border:none;width:100%;height:100%;min-height:300px;\"><br \/>\n\t<\/iframe>\n<\/div>\n\n\t\t\t <section class=\"citations-section\" role=\"contentinfo\">\n\t\t\t <h3>Candela Citations<\/h3>\n\t\t\t\t\t <div>\n\t\t\t\t\t\t <div id=\"citation-list-3370\">\n\t\t\t\t\t\t\t <div class=\"licensing\"><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Shared previously<\/div><ul class=\"citation-list\"><li>Biology 2e. <strong>Provided by<\/strong>: OpenStax. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\">http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em>. <strong>License Terms<\/strong>: Access for free at https:\/\/openstax.org\/books\/biology-2e\/pages\/1-introduction<\/li><\/ul><\/div>\n\t\t\t\t\t\t <\/div>\n\t\t\t\t\t <\/div>\n\t\t\t <\/section>","protected":false},"author":17,"menu_order":15,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"Biology 2e\",\"author\":\"\",\"organization\":\"OpenStax\",\"url\":\"http:\/\/cnx.org\/contents\/185cbf87-c72e-48f5-b51e-f14f21b5eabd@10.8\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"Access for free at https:\/\/openstax.org\/books\/biology-2e\/pages\/1-introduction\"}]","CANDELA_OUTCOMES_GUID":"c94b19f3-07cd-457c-9c3e-6072833bf2f3, acfb43fc-e1a1-4f61-97a9-eda9f9271915","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-3370","chapter","type-chapter","status-publish","hentry"],"part":161,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/3370","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/users\/17"}],"version-history":[{"count":10,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/3370\/revisions"}],"predecessor-version":[{"id":8742,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/3370\/revisions\/8742"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/parts\/161"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/3370\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/media?parent=3370"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapter-type?post=3370"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/contributor?post=3370"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/license?post=3370"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}