Radiation drive – Wikipedia

Components of the radiation drive of global warming in 2010–2019 relative to 1850–1900 according to the sixth status report of the IPCC; All drives result from human activity

The Radiation drive (engl. radiative forcing ) is a measure of the change in the earth’s energy balance by changing the effect of the radiation from space and is measured in W/m². The term radiative forcing or. climate forcing was introduced by the IPCC ^[first] In order to describe the influence of external factors on the radiation balance or the climate system of the earth as part of the climate studies. Such factors can be the changed concentration of greenhouse gases and aerosols, changed (absorbed) solar radiation in W/m² or a changed albedo. With regard to the solar radiation, a distinction must be made between the solar constant and the radiation actually reaching the earth’s surface, since the atmosphere reflects a part directly and the non -reflected radiation dampens, see the radiation balance. Inequality in the radiation balance sheet has the potential to bring about changes in climate parameters and thus a new state of balance of the climate system: an increased radiation drive leads to heating of the earth, a reduced radiation drive to cool down.

Causes of global warming (1750–2011) (as of 2018)

The radiation drive is a so -called use in earth system science language use Forcing , d. H. A system acting from the outside on a system Kraft that this system in a certain one Direction guides. For example, the solar radiation affects the surface temperature of the earth or the moon and controls it indirectly.

In the context of global warming, the term is to be applied to changes in the radiation balance of the surface tropospheric system, which are caused by external factors. It is assumed that there is no change in stratospheric dynamics and that there are no feedback in this area; Changes in the atmospheric amount of water and distribution, which result from the dynamics of the radiation drive, are also not taken into account.

The radiation drive (RF for radiative forcing , also

) can via a linear relationship with the change in global balance temperature on the earth’s surface (

) can be linked: ^[2]

${displaystyle Delta T_{S}=lambda Delta F}$

With λ = parameter of climate sensitivity with the unit K/(W/M ² ).

The one through the increase of the CO ₂ -Concentrations caused radiation drive can be approximately calculated as follows: ^{[first] [3]}

${displaystyle Delta F=5,35{mathrm {W} over mathrm {m} ^{2}}cdot ln {C over C_{0}}}$

With C = CO ₂ -Concentration of the atmosphere to be considered in PPM, C ₀ = Output concentration of the comparison atmosphere in ppm,

= resulting radiation drive in W/m².

The relationship between the CO ₂ -In concentration and the instantane radiation drive is logarithmic (for concentrations up to about the eight times of the current value of 400 ppm). ^[4]

Of all climate factors that have been changed since industrialization began, the increase in the CO ₂ -Incentrations of C ₀ = 278 ppm in 1750 by about 40% C = 391 ppm in 2011 with

≈ 1,82 W/m ² (± 0,19 W/m ² ) the largest radiation drive and accordingly has the largest proportion of global warming. ^[5]

Radiation drive in the period 1951–2010 in accordance with IPCC, AR5.

In the fifth state of affairs of the IPCC, the entire man -made radiation drive will be estimated with 2.3 W/m² in the period 1750 to 2011 (i.e. after withdrawing also cooling effects, e.g. by aerosols). For comparison: changes in the solar radiation caused a radiation drive of 0.05 W/m² in the same period, which corresponds to about 2 percent; Sun activity has even declined since the middle of the 20th century. ^[6] Gross caused all emitted durable greenhouse gases a radiation drive of 2.83 W/m². The most important greenhouse gas is CO ₂ With 1.82 W/m², followed by methane with 0.48 W/m². Halogenic fabrics cause a radiation drive of 0.36 W/m², laughing gas 0.17 W/m². Also responsible for a positive radiation drive are hydrocarbons, but the contribution is now decreasing after a massive decline in global production. Of the short -lived greenhouse gases, Ozon, the production of which is stimulated by nitrogen oxides, carbon monoxide or hydrocarbons, has the highest radiation drive with 0.4 W/m². A negative (i.e. cooling) radiation drive in the amount of −0.9 W/m² cause aerosols. ^[7]

1. ↑ ^{a b} IPCC Third Assessment Report, Working Group I: The Scientific Basis, Kapitel 6.3.1, Carbon Dioxide, Chapter 6: Radiative Forcing of Climate Change , Pp. 356–358, accessed on May 10, 2018.
2. ↑ Forster, P., V. Ramaswamy, P. Artaxo, T. Berntsen, R. Betts, D. W. Fahey, J. Haywood, J. Lean, D. C. Lowe, G. Myhre, J. Nganga, R. Prinn, G. Raga, M. Schulz and R. Van Dorland: Changes in Atmospheric Constituents and in Radiative Forcing. In: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K. B. Averyt, M. Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. Online (PDf 7.7)
3. ↑ G. Myhre u. a.: Anthropogenic and Natural Radiative Forcing . In: T. F. Stocker (ed.): Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change . 2013, Chapter 8 Supplementary Material – 8.SM.11.3.1 Anthropogenic and Natural Radiative Forcing Metric Values for Carbon Dioxide, S. 8SM-16 ( IPCC.ch ).
4. ↑ Huang, Yi; Bani Shahabadi, Maziar (28 November 2014). “Why logarithmic?”. J. Geophys. Res. Atmospheres. 119 (24): 13, 683–89
5. ↑ G. Myhre u. a.: Anthropogenic and Natural Radiative Forcing . In: T. F. Stocker (ed.): Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change . two thousand and thirteen, S. 676–677, 696–698 ( IPCC.ch ).
6. ↑ IPCC, 2013: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 56: “The best estimate of RF [radiative forcing, Strahlungsantrieb] from TSI [total solar irradiance, gesamte Sonneneinstrahlung] changes over the industrial era is 0.05 [0.00 to 0.10] W m–2 [W/m²] (medium confidence), which includes greater RF up to around 1980 and then a small downward trend.”
7. ↑ Ar5, zit. Nach: Mojib Latif: Do we get the climate out of time? , in: Klaus Wiegandt (ed.), Courage to sustainability. 12 ways into the future . Frankfurt am Main 2016, 80–112, S. 101–104.