Anthropogenic Causes of Climate Change

    Typically, climate change happened gradually over millions of years. Today's climatic changes are fast and mostly anthropogenic. Evidence demonstrates that climate change is taking place, but what causes it? Since the late 1800s, scientists have anticipated that changes in human-generated greenhouse gases in the atmosphere will likely lead to climate change, as changes in these gases have always the case in geological history. In the mid-1900s systemic measurements emerged, confirming that carbon dioxide manufacturer was building up in the atmosphere and in other earth systems, including as forests and seas.

    In the late 1900's and the early 2000's, anthropogenic climate change theory was consolidated to reflect the predicted increases in the temperature of a thousand ground-based investigations and continuous soil and ocean observations. Theories develop and adapt with the provision of new data and new technologies, but they represent the state of thought in this subject. The theory of anthropogenic climate change holds that people cause most of the present climatic changes via combustion of fossil fuels like coal, oil and natural gas.

    The vast majority of the climactic research shows that human activity causes fast climate changes, leading to significant damage to the ecosystem. The scientists on the topic are strongly agreed. Studies released in peer reviews reveal that 97% of climate experts believe that human actions are the cause of climate warming trend. The relationship between greenhouse gas emissions from human products and the changing modern climate is not explained as an alternative. The viewpoint was endorsed by prominent scientific groups, including the American National Academy, formed in 1863 by President Lincoln's act of Congress. The National Academy of Science was commissioned by Congress "to advise the government independently and objectively on scientific-technological issues." The National Academy of Science is therefore the main authority in the field of scientific policy advising.

    One method we know that the increased emissions of greenhouse gases are caused by human activity is via isotope signatures. For example, the ratio of stable carbon 13 fossil fuels to carbon 12 (13C/12C) differs from the current stable atmospheric carbon ratio. Since the 1980s, isotope carbon fingerprints have been used in studies to identify anthropogenic carbon in the atmosphere. Isotope data on the Antarctic Ice Sheet indicate stable isotope signatures of ~1000 AD to ~1800 AD and the steady isotope signature gradually shifting from 1800 to 1950. These shifts indicate that the atmosphere is becoming more similar to fossil carbon isotope signature

Figure 1 Isotopic attribution of natural and human drivers for climate change.

    Since pre-industrial periods, anthropogenic greenhouse gas emissions have grown because of world economic expansion and growth in the population. The main greenhouse gas, carbon dioxide, atmospheric concentrations are at unprecedented levels not witnessed in at least 800,000 years. Pre-industrial carbon dioxide levels were around 278 parts a million (ppm).

    For the first time in 2016, carbon dioxide reached over 400 ppm all year round. Atmospheric Carbon measurements at the Mauna Loa Carbon Dioxide Observatory indicate a steady rise from 315 ppm in 1957 to 410 ppm in 2017. Today's daily reading at Daily CO2 is shown. During warm weather, carbon dioxide varied from around 185 ppm in ice ages to 300 ppm on the basis of the ice core record over 800,000 years. See NOAA data accuracy animated over the past 800,000 years below carbon dioxide trends.

Figure 2 Total economically responsible anthropogenic greenhouse gas emissions (GHGs) in 2010. The circle represents direct GHG emission shares of five economic sectors (as a percentage of the overall anthropogenic GHG emissions) in 2010. The drawdown illustrates how the electricity and heat generation portion of indirect CO2 emissions (in% of total anthropogenic GHG emissions) is allocated to the final energy consumption sectors. AFOLU is farming, forestry and other land use (Source: Pachauri et al., 2014).

    Combustion of fossil fuel and industrial activities accounted for 78% of all emissions since 1970. The main sectors of the economy are the generation of electricity and heat (25%); agriculture, forestry and land usage (24%), industry (21%); cars (14%); other production of energy (9%); and building (6.4 %). Over 50 years have gone by with more than half of greenhouse gas emitted

    Sadly, efforts to reduce climate change need political action, despite scientific unanimity. Despite the rising concern about climate change, mitigation initiatives, laws and international agreements in certain locations have decreased emissions, however global greenhouse gas emissions continue to climb in the less developed globe. In reality, the most significant gains since 1970 have occurred between 2000 and 2010.

Figure 3 Annual GNC emissions per annum (GtCO 2 / year) from the combustion, production and flare of fossil fuel, forest and other land use, 1850–2011 in gigatonne of CO2-equivalent annually (GtCO2 / year). Bars and whiskers are indicated to be cumulative emissions and their uncertainty.

Figure 4 Annual CO2 emissions from large countries and the rest of the globe from 1959-2020 in fossil fuels and industries in milliards of tons of CO2 per year (GtCO2). Note the early projections for 2020 figures. World Carbon Project data.