Ozone. Carbon monoxide. Instrumental temperature record. Instrumental global surface temperature record since widespread reliable measurements began in the late 19th century; see also [1] The X axis represents time, and the Y axis represents the temperature anomaly (departure from 1961-1990 baseline of 14.0°C, Jones et al. 1999).
Watch how summer temperatures in the Northern Hemisphere change from 1955 to 2011. "Hot" (orange), "very hot" (red) "extremely hot" (brown) "average" (white), unusually "cold" (light blue), "very cold" (dark blue) and "extremely cold" (purple). The instrumental temperature record shows fluctuations of the temperature of earth's climate system. Initially the instrumental temperature record only documented land and sea surface temperature, but in recent decades instruments have also begun recording sub-surface ocean temperature.
Global records databases[edit] Calculating the global temperature[edit] Average Monthly Land surface temperatures from February 2000 to December 2013. Absolute temperatures v. anomalies[edit] Climateprediction.net. The project relies on the volunteer computing model using the BOINC framework where voluntary participants agree to run some processes of the project at the client-side in their personal computers after receiving tasks from the server-side for treatment. CPDN, which is run primarily by Oxford University in England, has harnessed more computing power and generated more data than any other climate modelling project.[4] It has produced over 100 million model years of data so far.[5] As of December 2010[update], there are more than 32,000 active participants from 147 countries with a total BOINC credit of more than 14 billion, reporting about 90 teraflops (90 trillion operations per second) of processing power.[6] Aims[edit] IPCC graphic of uncertainty ranges with various models over time.
Climateprediction.net is aiming to reduce the ranges and produce better probability information. As shown in the graph above, the various models have a fairly wide distribution of results over time. CPView.
Global climate model. Climate models are systems of differential equations based on the basic laws of physics, fluid motion, and chemistry. To “run” a model, scientists divide the planet into a 3-dimensional grid, apply the basic equations, and evaluate the results. Atmospheric models calculate winds, heat transfer, radiation, relative humidity, and surface hydrology within each grid and evaluate interactions with neighboring points.[1] Note on nomenclature[edit] The initialism GCM stands originally for general circulation model.
Recently, a second meaning has come into use, namely global climate model. While these do not refer to the same thing, General Circulation Models are typically the tools used for modelling climate, and hence the two terms are sometimes used as if they were interchangeable. History: general circulation models[edit] Atmospheric vs oceanic models[edit] There are both atmospheric GCMs (AGCMs) and oceanic GCMs (OGCMs). Modelling trends[edit] Model structure[edit] Model grids[edit] Global-warming potential. Global-warming potential (GWP) is a relative measure of how much heat a greenhouse gas traps in the atmosphere. It compares the amount of heat trapped by a certain mass of the gas in question to the amount of heat trapped by a similar mass of carbon dioxide.
A GWP is calculated over a specific time interval, commonly 20, 100 or 500 years. GWP is expressed as a factor of carbon dioxide (whose GWP is standardized to 1). For example, the 20 year GWP of methane is 86, which means that if the same mass of methane and carbon dioxide were introduced into the atmosphere, that methane will trap 86 times more heat than the carbon dioxide over the next 20 years.[1] The substances subject to restrictions under the Kyoto protocol either are rapidly increasing their concentrations in Earth's atmosphere or have a large GWP.
The GWP depends on the following factors: Thus, a high GWP correlates with a large infrared absorption and a long atmospheric lifetime. Calculating the global-warming potential[edit] Greenhouse gas. Since the beginning of the Industrial Revolution (taken as the year 1750), the burning of fossil fuels and extensive clearing of native forests has contributed to a 40% increase in the atmospheric concentration of carbon dioxide, from 280 ppm in 1750 to 392.6 ppm in 2012.[5][6] It has now reached 400 ppm in the northern hemisphere.
In the Solar System, the atmospheres of Venus, Mars, and Titan also contain gases that cause a greenhouse effect, though Titan's atmosphere has an anti-greenhouse effect that reduces the warming. Gases in Earth's atmosphere[edit] Greenhouse gases[edit] Greenhouse gases are those that can absorb and emit infrared radiation,[1] but not radiation in or near the visible spectrum. In order, the most abundant greenhouse gases in Earth's atmosphere are: Non-greenhouse gases[edit] Although contributing to many other physical and chemical reactions, the major atmospheric constituents, nitrogen (N 2), oxygen (O 2), and argon (Ar), are not greenhouse gases. ) (all in kg/s):