{"id":3369,"date":"2017-02-14T20:17:41","date_gmt":"2017-02-14T20:17:41","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/wm-biology2\/?post_type=chapter&#038;p=3369"},"modified":"2024-04-26T02:49:40","modified_gmt":"2024-04-26T02:49:40","slug":"evidence-for-global-climate-change","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/wm-biology2\/chapter\/evidence-for-global-climate-change\/","title":{"raw":"Evidence for Global Climate Change","rendered":"Evidence for Global Climate Change"},"content":{"raw":"<div class=\"textbox learning-objectives\">\r\n<h3>Learning Outcomes<\/h3>\r\n<ul>\r\n \t<li>Identify evidence for global climate change<\/li>\r\n<\/ul>\r\n<\/div>\r\n<p id=\"fs-idm8851136\">Since scientists cannot go back in time to directly measure climatic variables, such as average temperature and precipitation, they must instead indirectly measure temperature. To do this, scientists rely on\u00a0<em data-effect=\"italics\">historical evidence of Earth\u2019s past climate.<\/em><\/p>\r\n<p id=\"fs-idm51904624\">Antarctic ice cores are a key example of such evidence for climate change. These ice cores are samples of\u00a0<em data-effect=\"italics\">polar ice<\/em>\u00a0obtained by means of drills that reach thousands of meters into ice sheets or high mountain glaciers. Viewing the ice cores is like traveling backwards through time; the deeper the sample, the earlier the time period. Trapped within the ice are air bubbles and other biological evidence that can reveal temperature and carbon dioxide data. Antarctic ice cores have been collected and analyzed to indirectly estimate the temperature of the Earth over the past 400,000 years (Figure 1a). The 0 \u00b0C on this graph refers to the long-term average. Temperatures that are greater than 0 \u00b0C exceed Earth\u2019s long-term average temperature. Conversely, temperatures that are less than 0 \u00b0C are less than Earth\u2019s average temperature. This figure shows that there have been periodic cycles of increasing and decreasing temperature.<\/p>\r\n\r\n\r\n[caption id=\"\" align=\"aligncenter\" width=\"424\"]<img id=\"3\" class=\"\" src=\"https:\/\/openstax.org\/resources\/a623adc09b7354200185309dc1f7ae5361071cf2\" alt=\"In the first image, a group of scientists uses a drill to extract an ice core in a polar environment. In the second, an ice core is displayed, showing air bubbles trapped within.\" width=\"424\" height=\"528\" data-media-type=\"image\/png\" \/> Figure 1. Scientists drill for ice cores in polar regions. The ice contains air bubbles and biological substances that provide important information for researchers. (credit: a: Helle Astrid Kj\u00e6r; b: National Ice Core Laboratory, USGS)[\/caption]\r\n<p id=\"fs-idp94027152\">Before the late 1800s, the Earth has been as much as 9 \u00b0C cooler and about 3 \u00b0C warmer. Note that the graph in\u00a0Figure 2b shows that the atmospheric concentration of carbon dioxide has also risen and fallen in periodic cycles. Also note the relationship between carbon dioxide concentration and temperature.\u00a0Figure 2b shows that carbon dioxide levels in the atmosphere have historically cycled between 180 and 300 parts per million (ppm) by volume.<\/p>\r\n\r\n\r\n[caption id=\"attachment_3374\" align=\"aligncenter\" width=\"1024\"]<img class=\"size-large wp-image-3374\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/02\/14201234\/Figure_44_05_01ab-1024x363.jpg\" alt=\" Top graph plots temperature in degrees Celsius versus years before present, beginning 400,000 years ago. Temperature shows a cyclical variation, from about 2 degrees Celsius above today\u2019s average temperature, to about 8 degrees below. Carbon dioxide levels also show a cyclical variation. Today, the carbon dioxide concentration is about 395 parts per million. In the past, it cycled between 180 and 300 parts per million. The temperature and carbon dioxide cycles, which repeat at about a hundred thousand year scale, closely mirror one another.\" width=\"1024\" height=\"363\" \/> Figure 2. Ice at the Russian Vostok station in East Antarctica was laid down over the course 420,000 years and reached a depth of over 3,000 m. By measuring the amount of CO<sub>2<\/sub> trapped in the ice, scientists have determined past atmospheric CO<sub>2<\/sub> concentrations. Temperatures relative to modern day were determined from the amount of deuterium (an isotope of hydrogen) present.[\/caption]\r\n\r\n<span id=\"fs-idp225286032\" data-type=\"media\" data-alt=\" Top graph plots temperature in degrees Celsius versus years before present, beginning 400,000 years ago. Temperature shows a cyclical variation, from about 2 degrees Celsius above today\u2019s average temperature, to about 8 degrees below. Carbon dioxide levels also show a cyclical variation. Today, the carbon dioxide concentration is about 395 parts per million. In the past, it cycled between 180 and 300 parts per million. The temperature and carbon dioxide cycles, which repeat at about a hundred thousand year scale, closely mirror one another.\"><\/span>Figure 2a\u00a0does not show the last 2,000 years with enough detail to compare the changes of Earth\u2019s temperature during the last 400,000 years with the temperature change that has occurred in the more recent past. Two significant temperature anomalies, or\u00a0<em data-effect=\"italics\">irregularities<\/em>, have occurred in the last 2,000 years. These are the\u00a0<em data-effect=\"italics\">Medieval Climate Anomaly<\/em>\u00a0(or the Medieval Warm Period) and the\u00a0<em data-effect=\"italics\">Little Ice Age<\/em>. A third temperature anomaly aligns with the\u00a0<em data-effect=\"italics\">Industrial Era<\/em>. The Medieval Climate Anomaly occurred between 900 and 1300 AD. During this time period, many climate scientists think that slightly warmer weather conditions prevailed in many parts of the world; the higher-than-average temperature changes varied between 0.10 \u00b0C and 0.20 \u00b0C above the norm. Although 0.10 \u00b0C does not seem large enough to produce any noticeable change, it did free seas of ice. Because of this warming, the Vikings were able to colonize Greenland.\r\n\r\n[caption id=\"attachment_3375\" align=\"alignright\" width=\"400\"]<img class=\"wp-image-3375\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/02\/14201322\/Figure_44_05_02.jpg\" alt=\" Atmospheric carbon dioxide concentration is plotted against year, from 1960 to 2010. Carbon dioxide concentration has steadily risen in the timeframe shown.\" width=\"400\" height=\"315\" \/> Figure 3. The atmospheric concentration of CO<sub>2<\/sub> has risen steadily since the beginning of industrialization.[\/caption]\r\n<p id=\"fs-idp73981232\">The\u00a0<span id=\"term2253\" data-type=\"term\">Little Ice Age<\/span>\u00a0was a cold period that occurred between 1550 AD and 1850 AD. During this time, a slight cooling of a little less than 1 \u00b0C was observed in North America, Europe, and possibly other areas of the Earth. This 1 \u00b0C change in global temperature is a seemingly small deviation in temperature (as was observed during the Medieval Climate Anomaly); however, it also resulted in noticeable climatic changes. Historical accounts reveal a time of exceptionally harsh winters with much snow and frost.<\/p>\r\n<p id=\"fs-idp30297776\">The\u00a0<em data-effect=\"italics\">Industrial Revolution<\/em>, which began around 1750, was characterized by changes in much of human society. Advances in agriculture increased the food supply, which improved the standard of living for people in Europe and the United States. New technologies were invented that provided jobs and cheaper goods. These new technologies were powered using fossil fuels, especially coal. The Industrial Revolution starting in the early nineteenth century ushered in the beginning of the Industrial Era. When a fossil fuel is burned, carbon dioxide is released. With the beginning of the Industrial Era, atmospheric carbon dioxide began to rise (Figure 3).<\/p>\r\n\r\n<div class=\"textbox tryit\">\r\n<h3>Try It<\/h3>\r\nhttps:\/\/assess.lumenlearning.com\/practice\/7219f3c1-d9a5-4c47-81a3-3be32057bc4f\r\n<\/div>","rendered":"<div class=\"textbox learning-objectives\">\n<h3>Learning Outcomes<\/h3>\n<ul>\n<li>Identify evidence for global climate change<\/li>\n<\/ul>\n<\/div>\n<p id=\"fs-idm8851136\">Since scientists cannot go back in time to directly measure climatic variables, such as average temperature and precipitation, they must instead indirectly measure temperature. To do this, scientists rely on\u00a0<em data-effect=\"italics\">historical evidence of Earth\u2019s past climate.<\/em><\/p>\n<p id=\"fs-idm51904624\">Antarctic ice cores are a key example of such evidence for climate change. These ice cores are samples of\u00a0<em data-effect=\"italics\">polar ice<\/em>\u00a0obtained by means of drills that reach thousands of meters into ice sheets or high mountain glaciers. Viewing the ice cores is like traveling backwards through time; the deeper the sample, the earlier the time period. Trapped within the ice are air bubbles and other biological evidence that can reveal temperature and carbon dioxide data. Antarctic ice cores have been collected and analyzed to indirectly estimate the temperature of the Earth over the past 400,000 years (Figure 1a). The 0 \u00b0C on this graph refers to the long-term average. Temperatures that are greater than 0 \u00b0C exceed Earth\u2019s long-term average temperature. Conversely, temperatures that are less than 0 \u00b0C are less than Earth\u2019s average temperature. This figure shows that there have been periodic cycles of increasing and decreasing temperature.<\/p>\n<div style=\"width: 434px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" id=\"3\" class=\"\" src=\"https:\/\/openstax.org\/resources\/a623adc09b7354200185309dc1f7ae5361071cf2\" alt=\"In the first image, a group of scientists uses a drill to extract an ice core in a polar environment. In the second, an ice core is displayed, showing air bubbles trapped within.\" width=\"424\" height=\"528\" data-media-type=\"image\/png\" \/><\/p>\n<p class=\"wp-caption-text\">Figure 1. Scientists drill for ice cores in polar regions. The ice contains air bubbles and biological substances that provide important information for researchers. (credit: a: Helle Astrid Kj\u00e6r; b: National Ice Core Laboratory, USGS)<\/p>\n<\/div>\n<p id=\"fs-idp94027152\">Before the late 1800s, the Earth has been as much as 9 \u00b0C cooler and about 3 \u00b0C warmer. Note that the graph in\u00a0Figure 2b shows that the atmospheric concentration of carbon dioxide has also risen and fallen in periodic cycles. Also note the relationship between carbon dioxide concentration and temperature.\u00a0Figure 2b shows that carbon dioxide levels in the atmosphere have historically cycled between 180 and 300 parts per million (ppm) by volume.<\/p>\n<div id=\"attachment_3374\" style=\"width: 1034px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-3374\" class=\"size-large wp-image-3374\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/02\/14201234\/Figure_44_05_01ab-1024x363.jpg\" alt=\"Top graph plots temperature in degrees Celsius versus years before present, beginning 400,000 years ago. Temperature shows a cyclical variation, from about 2 degrees Celsius above today\u2019s average temperature, to about 8 degrees below. Carbon dioxide levels also show a cyclical variation. Today, the carbon dioxide concentration is about 395 parts per million. In the past, it cycled between 180 and 300 parts per million. The temperature and carbon dioxide cycles, which repeat at about a hundred thousand year scale, closely mirror one another.\" width=\"1024\" height=\"363\" \/><\/p>\n<p id=\"caption-attachment-3374\" class=\"wp-caption-text\">Figure 2. Ice at the Russian Vostok station in East Antarctica was laid down over the course 420,000 years and reached a depth of over 3,000 m. By measuring the amount of CO<sub>2<\/sub> trapped in the ice, scientists have determined past atmospheric CO<sub>2<\/sub> concentrations. Temperatures relative to modern day were determined from the amount of deuterium (an isotope of hydrogen) present.<\/p>\n<\/div>\n<p><span id=\"fs-idp225286032\" data-type=\"media\" data-alt=\"Top graph plots temperature in degrees Celsius versus years before present, beginning 400,000 years ago. Temperature shows a cyclical variation, from about 2 degrees Celsius above today\u2019s average temperature, to about 8 degrees below. Carbon dioxide levels also show a cyclical variation. Today, the carbon dioxide concentration is about 395 parts per million. In the past, it cycled between 180 and 300 parts per million. The temperature and carbon dioxide cycles, which repeat at about a hundred thousand year scale, closely mirror one another.\"><\/span>Figure 2a\u00a0does not show the last 2,000 years with enough detail to compare the changes of Earth\u2019s temperature during the last 400,000 years with the temperature change that has occurred in the more recent past. Two significant temperature anomalies, or\u00a0<em data-effect=\"italics\">irregularities<\/em>, have occurred in the last 2,000 years. These are the\u00a0<em data-effect=\"italics\">Medieval Climate Anomaly<\/em>\u00a0(or the Medieval Warm Period) and the\u00a0<em data-effect=\"italics\">Little Ice Age<\/em>. A third temperature anomaly aligns with the\u00a0<em data-effect=\"italics\">Industrial Era<\/em>. The Medieval Climate Anomaly occurred between 900 and 1300 AD. During this time period, many climate scientists think that slightly warmer weather conditions prevailed in many parts of the world; the higher-than-average temperature changes varied between 0.10 \u00b0C and 0.20 \u00b0C above the norm. Although 0.10 \u00b0C does not seem large enough to produce any noticeable change, it did free seas of ice. Because of this warming, the Vikings were able to colonize Greenland.<\/p>\n<div id=\"attachment_3375\" style=\"width: 410px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-3375\" class=\"wp-image-3375\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/1223\/2017\/02\/14201322\/Figure_44_05_02.jpg\" alt=\"Atmospheric carbon dioxide concentration is plotted against year, from 1960 to 2010. Carbon dioxide concentration has steadily risen in the timeframe shown.\" width=\"400\" height=\"315\" \/><\/p>\n<p id=\"caption-attachment-3375\" class=\"wp-caption-text\">Figure 3. The atmospheric concentration of CO<sub>2<\/sub> has risen steadily since the beginning of industrialization.<\/p>\n<\/div>\n<p id=\"fs-idp73981232\">The\u00a0<span id=\"term2253\" data-type=\"term\">Little Ice Age<\/span>\u00a0was a cold period that occurred between 1550 AD and 1850 AD. During this time, a slight cooling of a little less than 1 \u00b0C was observed in North America, Europe, and possibly other areas of the Earth. This 1 \u00b0C change in global temperature is a seemingly small deviation in temperature (as was observed during the Medieval Climate Anomaly); however, it also resulted in noticeable climatic changes. Historical accounts reveal a time of exceptionally harsh winters with much snow and frost.<\/p>\n<p id=\"fs-idp30297776\">The\u00a0<em data-effect=\"italics\">Industrial Revolution<\/em>, which began around 1750, was characterized by changes in much of human society. Advances in agriculture increased the food supply, which improved the standard of living for people in Europe and the United States. New technologies were invented that provided jobs and cheaper goods. These new technologies were powered using fossil fuels, especially coal. The Industrial Revolution starting in the early nineteenth century ushered in the beginning of the Industrial Era. When a fossil fuel is burned, carbon dioxide is released. With the beginning of the Industrial Era, atmospheric carbon dioxide began to rise (Figure 3).<\/p>\n<div class=\"textbox tryit\">\n<h3>Try It<\/h3>\n<p>\t<iframe id=\"assessment_practice_7219f3c1-d9a5-4c47-81a3-3be32057bc4f\" class=\"resizable\" src=\"https:\/\/assess.lumenlearning.com\/practice\/7219f3c1-d9a5-4c47-81a3-3be32057bc4f?iframe_resize_id=assessment_practice_id_7219f3c1-d9a5-4c47-81a3-3be32057bc4f\" 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-3369\">\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":14,"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, 4b59535f-ea5b-4b73-8502-ee10bff4a8b5","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-3369","chapter","type-chapter","status-publish","hentry"],"part":161,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/3369","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":8,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/3369\/revisions"}],"predecessor-version":[{"id":8758,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapters\/3369\/revisions\/8758"}],"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\/3369\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/media?parent=3369"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/pressbooks\/v2\/chapter-type?post=3369"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/contributor?post=3369"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/wm-biology2\/wp-json\/wp\/v2\/license?post=3369"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}