Natural Factors Causing Climate Change – Climate change is caused by the natural greenhouse effect and its disruption by human activity current energy flow in W/m2
Note: Earth is constantly receiving energy from the Sun. Part of this energy that is not reflected by the atmosphere, especially clouds or the earth’s surface (oceans and continents), is absorbed by the earth’s surface, which is heated by absorption. On the other hand, surfaces and the atmosphere emit infrared radiation, which intensifies as the surfaces heat up. Some of this radiation is absorbed by certain gases and clouds and is then re-radiated towards the surface, contributing to its warming. This phenomenon is called the greenhouse effect.
- 1 Natural Factors Causing Climate Change
- 2 Climate Change: Evidence And Causes
- 3 Analysis: Why Scientists Think 100% Of Global Warming Is Due To Humans
Natural Factors Causing Climate Change
An increase in the concentration of greenhouse gases in the atmosphere due to anthropogenic emissions (see Glossary) increases the radiation of energy towards the land, which leads to an imbalance in the Earth’s radiation balance and causes an increase in the temperature of the Earth’s surface. The change in radiation due to climatic factors in relation to the reference year is called radiative forcing. A positive value of radiative forcing indicates a contribution to global warming. Total anthropogenic radiation is + 3.8 W/m2 for greenhouse gases and – 1.1 W/m2 for aerosols in 2019 compared to 1750, for a total of + 2.7 W/m2.
Climate Change: Evidence And Causes
With the exception of water vapor, greenhouse gases occupy less than 0.1% of the atmospheric volume. Water vapor, which varies between 0.4 and 4%, is the main greenhouse gas. Human activities have little direct effect on the variation in its concentration, but have a strong effect on the concentrations of other greenhouse gases.
Global warming potential (GWP, see Glossary) is the ratio between the energy returned to the earth by 1 kg of gas in 100 years and the energy returned by 1 kg of CO2. It depends on the radiative properties and lifetime of the gas in the atmosphere. For example, 1 kg of methane ( CH4 ) warms the atmosphere by up to 27 to 30 kg of CO2 after emissions. Although CO2 has the least global warming potential, it has contributed the most to global warming since 1750 due to the large amount of emissions released.
Note: This graph shows: (i) in square brackets, the size of the reservoir in billions of tonnes of CO2 in pre-industrial times in black and their cumulative change in red for the period 1750–2019; (ii) In the shape of an arrow, carbon fluxes between reservoirs represent billions of tonnes of CO2 per year (see glossary). Pre-industrial streams are black. Those associated with anthropogenic activity between 2011 and 2020 are in red.
Carbon fluxes into these reservoirs come from the natural carbon cycle plus perturbations associated with anthropogenic CO2 emissions (mainly the burning of fossil organic carbon stocks) that alter exchange fluxes or create new ones.
Climate Change Impacts On Plant Pathogens, Food Security And Paths Forward
Imbalance between emissions and CO2 storage capacity Net annual fluxes of anthropogenic CO2 (emissions to the atmosphere and sequestrations by land and ocean reservoirs) in the period 2011–2020
Note: The uncertainty of the increase in CO2 concentration in the atmosphere is very small (± 0.02 Gt CO2/year) and is not plotted.
Over the past ten years (2011–2020), human activity produced an average of 39 Gt CO2 per year, the atmosphere absorbed 19 Gt CO2, terrestrial reservoirs (vegetation and soil) 11 Gt CO2, and the oceans absorbed 10 Gt CO2. The atmosphere is the reservoir most affected by anthropogenic activity: it has absorbed about 50% of the carbon emitted over the past 60 years.
Globally, forests are a carbon store. The gross decline attributed to the Earth’s biosphere – i.e. primarily forests – offsets 29% of annual anthropogenic carbon emissions or about 11 Gt CO2 (Friedlingstein).
Analysis: Why Scientists Think 100% Of Global Warming Is Due To Humans
., 2022). Forests that remain forests are carbon sinks. By incorporating deforestation (the conversion of forest land to other uses), the forestry sector becomes a source of carbon. Deforestation through burning and decomposition of organic matter causes emissions associated with the loss of carbon stocks in forests. These net emissions (mainly from forests) account for about 14% of annual global anthropogenic carbon emissions (IPCC, 2022).
In France, net carbon sequestration in forest biomass for 2020 is estimated at 30.4 Mt CO2 eq., while sinks in wood products are 0.8 Mt CO2 eq. Overall, forests and wood products account for 8% of national greenhouse gas emissions (land use, land-use change and forestry, excluding LULUCF,
Since the development of industrial activities, land and sea reservoirs have absorbed more than half of anthropogenic emissions. The remaining emissions persist into the atmosphere and increase greenhouse gas concentrations. Milankovitch’s theory explains 3 cyclical changes in Earth’s orbit and tilt that cause climate fluctuations over thousands of years to tens of thousands of years. You learned about these orbital changes in temperature in the Time module. These fluctuations include a change in the shape of the Earth’s orbit (eccentricity) every ~100,000 years, a tilt of the Earth’s axis (obliquity) every ~41,000 years, and a wobble (precession) of the Earth’s axis every about 23,000 years. Milankovitch proposed that the Ice Age began when the three cycles aligned, favoring a longer period of more sunlight in winter and less sunlight in summer at 65°N latitude. For northern latitudes, these conditions favor slightly higher temperatures but more water vapor in the air, leading to more snow. Relatively cool summers in northern latitudes encourage less snowmelt and glacier formation.
The figure above shows the alignment of each orbital change during the glacial and interglacial periods. The interplay of the three orbital cycles affects the amount of solar radiation received at different latitudes during the year. The amount of solar radiation reaching 65°N in the Northern Hemisphere appears to control the advance and retreat of glaciers and ice sheets.
What Causes The Earth’s Climate To Change?
Volcanic eruptions release carbon dioxide, but they can also release aerosols such as volcanic ash or dust and sulfur dioxide. Aerosols are liquids and solids that are suspended in the air. They can also include soot, dust, salt crystals, bacteria and viruses. Aerosols scatter incoming solar radiation, resulting in a slight cooling effect. Volcanic aerosols can block a percentage of solar radiation and cause cooling that can last 1-2 years.
The year 1816, often referred to as the “year without a summer”, occurred after the violent eruption of Mount Tambora in Indonesia. It was probably the largest known eruption in the history of human civilization. Snowfall in the northeastern United States and Canada in June caused regional crop damage, food shortages, and increased mortality. Relatively cool summers have also followed other famous volcanic eruptions (such as the 1883 eruption of Krakatau in Indonesia and the 1991 eruption of Mount Pinatubo in the Philippines).
) in the stratosphere. Sulfur dioxide combines with water vapor to form sulfuric acid (H2SO
) and sulfate particles, collectively known as sulfur aerosols. Winds transport these sulfur-containing aerosols eastward or westward around the planet. Because of this, volcanic eruptions at lower latitudes (closer to the equator) are more likely to cause hemispheric or global cooling. Volcanoes erupting at high latitudes (closer to the poles) are less likely to cool because sulfur-containing aerosols are restricted to air patterns around the poles.
What Is The Cause Of Climate Change?
The total amount of solar radiation changes very little. The energy emitted by the sun changes by only 1.3 W/m
. This change in solar radiation is related to the number of sunspots. Sunspots are dark areas on the surface of the Sun. A sunspot forms where an intense magnetic field weakens the flow of gas that carries thermal energy from the Sun’s interior. Sunspots appear darker because their temperature is lower than their surroundings.
About every 11 years, the number of sunspots changes from maximum to minimum. The Sun emits slightly more radiation during active sunspot periods. Because sunspots suppress heat, the heat flows to the surrounding areas, causing those areas to be brighter than normal and to radiate more heat. While more sunspots may contribute to a warmer global climate, fewer sunspots appear to be associated with a cooler global climate. About 300 years ago there was a period of low solar activity. This was called the Little Ice Age.
As tectonic plates move over geologic time scales, landmasses are moved to different positions and latitudes. These changes affect the global patterns of air and ocean water flow and the climate of the continents. One form of evidence for plate tectonics and an example of how plate tectonics affects climate is the location of coal mines. Coal mines originated millions of years ago in the tropics, but today they are found in high latitudes. In the Temperature Over Time module, you learned that the Northern Hemisphere has been warmer than the Southern Hemisphere since the Industrial Revolution. This is because the Northern Hemisphere has a large percentage of the Earth’s surface
Scientists: Strong Evidence That Human Caused Climate Change Intensified 2015 Heat Waves
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