Evidence of Climate Change

Human effect on the global climate is evident and increasing, with impacts observed amongst all continents and oceans.

^{Figure 1 - Human Activities on Earth}

Several of the observed shifts since the 1950s are unparalleled over decades to millennia.

The IPCC (Intergovernmental Panel on Climate Change) is 95% confident that mankind is now the primary cause of the recent global climate change. In fact, the more industrial activities disrupt the climate, the greater the chances of extreme, permanent and inevitable impacts for humans and the environment, and lengthy shifts in all climate system¹.

Scientists have been able to see the big picture thanks to Earth-orbiting satellites and other technical advancements, which have enabled them to gather a wide range of data about our world and its environment on a global scale. The signs of a changing environment are exposed in this body of evidence, which has been accumulated over several years. 

^{Figure 2 Ice melting in the North Pole}

Since the late 1800s, the planet's average surface temperature has risen by around 2.12 degrees Fahrenheit (1.18 degrees Celsius), due primarily to increased carbon dioxide pollution into the atmosphere and other human activities².  The last 40 years have experienced the most warming, with the last seven years being the warmest. 2016 and 2020 are tied for the warmest year ever recorded³.

Carbon dioxide and other gases' ability to absorb heat was shown in the mid-nineteenth century⁴. Many NASA instruments are based on their ability to control the flow of infrared energy through the atmosphere. There is no doubt that the levels of greenhouse gases would cause the Earth to burn.

Greenland, Antarctica, and tropical mountain glaciers have also produced ice cores that demonstrate how the Earth's atmosphere reacts to increases in greenhouse gas levels. Tree rings, ocean sediments, coral reefs, and layers of sedimentary rocks all provide ancient evidence. 

This ancient evidence, known as paleoclimate, shows that recent warming is about ten times faster than in the past. During the last Ice Age, carbon dioxide from human activities increased more than 250 times more than it did from natural causes⁵.

Rapid climate change is supported by persuasive evidence:

• Temperature Rise
• Warmer Oceans
• Retreat of glaciers
• Ice Sheets That Are Shrinking
• Rise of Sea Levels
• Reduced Snow Coverage
• Extreme weathers
• Arctic Sea Ice Melting
• Acidification of the Oceans

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^{1 -} 

• ^{PCC Fifth Assessment Report, Summary for Policymakers}
• ^{B.D. Santer et.al., “A search for human influences on the thermal structure of the atmosphere,” Nature vol 382, 4 July 1996, 39-46}
• ^{Gabriele C. Hegerl, “Detecting Greenhouse-Gas-Induced Climate Change with an Optimal Fingerprint Method,” Journal of Climate, v. 9, October 1996, 2281-2306}
• ^{V. Ramaswamy et.al., “Anthropogenic and Natural Influences in the Evolution of Lower Stratospheric Cooling,” Science 311 (24 February 2006), 1138-1141}
• ^{B.D. Santer et.al., “Contributions of Anthropogenic and Natural Forcing to Recent Tropopause Height Changes,” Science vol. 301 (25 July 2003), 479-483.}

^{2 -} 

• ^{https://www.ncdc.noaa.gov/monitoring-references/faq/indicators.php}
• ^{https://crudata.uea.ac.uk/cru/data/temperature/​}
• ^{http://data.giss.nasa.gov/gistemp}

^{3 - https://www.giss.nasa.gov/research/news/20170118/}

^{4 - In 1824, Joseph Fourier determined that at our distance from the Sun, an Earth-sized planet must be very cold. He speculated that something in the atmosphere was acting like an insulator. Eunice Foote discovered the blanket in 1856, demonstrating that the atmosphere's carbon dioxide and water vapor trap escaping infrared (heat) radiation. John Tyndall, a physicist, recognised Earth's natural greenhouse effect in the 1860s and proposed that small differences in atmospheric chemistry may cause climatic variations. Svante Arrhenius, a Swedish scientist, predicted that increases in ambient carbon dioxide levels could significantly alter surface temperature through the greenhouse effect in a landmark paper published in 1896. Guy Callendar attributed rising carbon dioxide levels in the atmosphere to global warming in 1938. Milutin Milankovic identified a correlation between ice ages and Earth's orbital characteristics in 1941. In 1956, Gilbert Plass proposed the Carbon Dioxide Theory of Climate Change.}

^{5 - Vostok ice core data; NOAA Mauna Loa CO2 record Gaffney, O.; Steffen, W. (2017). "The Anthropocene equation," The Anthropocene Review (Volume 4, Issue 1, April 2017), 53-
61.}