Talk:Global surface temperature

I've removed this content as I think it is covered much better in our other Wikipedia articles. I think it goes beyond the scope of this article:

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Warming oceans:

With the Earth's temperature increasing, the ocean has absorbed much of this increased heat, with the top 700 meters of ocean showing warming of 0.22 C (0.4 °F) since 1969.^[1] Expansion of the warm water, along with melting ice sheets, causes the sea level to rise.

The distribution of excess heat in the ocean is uneven, with the greatest ocean warming occurring in the southern hemisphere and contributing to the underground melting of the Antarctic ice shelf.^[2] The warming of sea water is also related to the thinning of ice shelves and sea ice, both of which have a further impact on the Earth's climate system. Finally, sea warming threatens marine ecosystems and human livelihoods.^[3] For example, warm water endangers the health of corals, which in turn endangers marine communities that depend on corals for shelter and food. Ultimately, people who rely on marine fisheries for their livelihoods and jobs may face the negative effects of ocean warming.

During the 20th century, the sea surface temperature increased for a century and continued to rise. From 1901 to 2015, the temperature increased by an average of 0.13 °F per decade. Since reliable observations began in 1880, the sea surface temperature has been higher than at any other time in the past three decades.^[4] As greenhouse gases absorb more energy from the sun, the ocean absorbs more heat, leading to rising sea surface temperatures and rising sea levels. Changes in ocean temperature and ocean currents brought about by climate change will lead to changes in the global climate pattern. For example, warmer waters may promote the development of stronger storms in the tropics, which may cause property loss and loss of life. Impacts related to sea level rise and severe storms are particularly relevant to coastal communities.

Shrinking ice sheets:

The Antarctic and Greenland ice sheets have decreased exponentially in mass. According to NASA's Gravity Recovery and Climate Experiment, it shows that Greenland has lost an average of 286 billion tons of ice per year.^[1] The expansion of the warm water and the melting ice sheets cause the sea level to rise.

The ice is changing everywhere on earth. Since 1912, the famous snow of Mount Kilimanjaro has melted more than 80%. The glaciers in the Garhwal Himalayas in India are retreating so fast that researchers believe that by 2035, most of the central and eastern Himalayas will actually disappear. For half a century, its range has dropped by about 10% in the past 30 years. NASA repeated laser altimeter readings showed that the edge of the Greenland ice sheet was shrinking. Now, the spring freshwater ice in the northern hemisphere breaks 9 days earlier than 150 years ago, while the autumn freeze is 10 days later. The melting of frozen ground caused land subsidence in parts of Alaska to exceed 15 feet (4.6 meters). From the Arctic to Peru, from Switzerland to the equatorial glacier in Manjaya, Indonesia, massive ice fields, monstrous glaciers, and sea ice are disappearing, fast.^[5]

When the temperature rises and the ice melts, more water flows into the ocean from glaciers and ice caps, and the sea water warms and expands in volume. According to the Intergovernmental Panel on Climate Change (IPCC), this combined effect has played a major role in raising the global average sea level by 4 to 8 inches (10 to 20 centimetres) in the past 100 years.

Greenland's meltwater may greatly affect the flow of huge ocean currents, which are called the Atlantic meridional overturning circulation or AMOC. Similar to a huge conveyor belt, AMOC helps transport hot water from tropical regions to the Arctic. Its important role in the global distribution of heat also makes it have a significant impact on global weather conditions-AMOC's hot water flow is largely due to the mild climate in places such as Western Europe. As fresh water pours into the ocean from the melting Greenland ice sheet, this may slow down the flow of water.^[6] At the same time, studies have shown that melting ice from Antarctica may disrupt the structure of the Southern Ocean. Because the density of fresh water is lower than that of salt water, a large amount of melt water may not be able to merge with the rest of the ocean, but form a layer of material attached to the water surface. This cold liquid traps heat underneath it and causes deeper layers to heat up. This increases the overall temperature of the ocean, which makes it less able to absorb CO₂ from the atmosphere. As a result, more CO₂ will remain in the atmosphere, leading to an increase in global warming. EMsmile (talk) 10:36, 15 December 2023 (UTC)

EMsmile (talk) 10:36, 15 December 2023 (UTC)

I've just made some drastic changes to the article because I don't think it should repeat the same content on the effects of warming that are already covered better in other articles. Therefore, I have added excerpts instead. What other content (if any) should still be added to this article, keeping in mind that we don't want to create more overlap with other articles than necessary. I can't really think of anything else but we could add more links and excerpts if needed. EMsmile (talk) 11:32, 15 December 2023 (UTC)

Most of the world did not get direct measurements until well into the 20th century. As such, it is misleading to claim that there has been direct measurements since 1880, as most of the world was simply not measured. 5.186.78.167 (talk) 09:51, 8 April 2024 (UTC)

You're right. I've changed it to "Series of reliable temperature measurements in some regions began in the 1850—1880 time frame (this is called the instrumental temperature record)." Please check if OK like this? EMsmile (talk) 09:37, 19 June 2024 (UTC)

I've just made some improvements to the readability of the lead and the lead's image caption. I've also made the lead a little bit longer. Pinging User:Efbrazil in case they have time to look at this as well. (This article is an example where the lead can remain pretty short, as the article is also short itself. It's not much more than just a definition of the term and then excerpts from other related articles. I think this is correct because otherwise we would introduce too much overlap with the other articles, e.g. instrumental temperature record, sea surface temperature) EMsmile (talk) 11:51, 16 April 2024 (UTC)

I've just completed the merger from Instrumental temperature record (see on the talk page there for previous discussions). I've also done some post-merge tidying work but more is probably needed to weed out any repetition. We also need to improve the new lead more. EMsmile (talk) 22:32, 23 August 2024 (UTC)

"estimated global average of near-surface air temperatures over land and sea ice, and sea surface temperature (SST) over ice-free ocean regions, with changes normally expressed as departures from a value over a specified reference period" The sea surface The sea surface temperature is the temperature of the water layer near the surface (no clear definition). At least that's how it is measured. 2003:E5:272D:4A00:CC84:FC88:7822:CF66 (talk) 21:45, 11 December 2024 (UTC)

what are you trying to say? What change to the article are you suggesting? EMsmile (talk) 22:13, 12 December 2024 (UTC)

Put simply, the global surface temperature (GST) is calculated by averaging the temperatures over sea (sea surface temperature) and land (surface air temperature).

Not over the sea, but in surface layer of the sea. 2003:E5:272D:4A00:81B6:866D:85F4:AE46 (talk) 10:24, 16 December 2024 (UTC)

I've changed it to this now (bolding to show the changed wording): Put simply, the global surface temperature (GST) is calculated by averaging the temperature at the surface layer of the ocean (sea surface temperature) and over land (surface air temperature).. Better? EMsmile (talk) 21:55, 21 December 2024 (UTC)

The global temperature record shows the fluctuations of the temperature of the atmosphere and the oceans through various spans of time.

In natural sciences and mathematics, fluctuation is understood to be the random or random-seeming change of a system variable compared to a reference variable that is approximately considered to be known. From this point of view, the term does not seem appropriate. Changes is better because they are usually not random changes. Furthermore, the GMST can only indicate changes in the near-surface layer. 79.127.158.218 (talk) 09:36, 28 December 2024 (UTC)

It is more of a description than a definition. A definition includes at least a description of the basic calculation method (e.g. weighted arithmetic mean). There are no different definitions for the GMST; it is calculated using different statistical methods.

See also: A. E. Allahverdyan, S. G. Gevorkian, Yu. A. Dyakov and Pao-Kuan Wang Thermodynamic definition of mean temperature Phys. Rev. E 108, 044112 – Published 6 October, 2023 DOI: https://doi.org/10.1103/PhysRevE.108.044112

The notion of mean temperature is crucial for a number of fields, including climate science, fluid dynamics, and biophysics. However, so far its correct thermodynamic foundation is lacking or even believed to be impossible. A physically correct definition should not be based on mathematical notions of the means (e.g., the mean geometric or mean arithmetic), because they are not unique, and they ignore the fact that temperature is an ordinal level variable. 79.127.158.218 (talk) 09:55, 28 December 2024 (UTC)

Soooo.... shouldn't the first paragraph in an article called "Global surface temperature" tell us, well, what that temperature actually is? It goes into the science of climate and how that relates to Anthropocene climate change, and that's all good, but when I see something referred to as "deviations from a number", it would be nice to actually say what that number is. Spearman (talk) 22:16, 4 February 2025 (UTC)

The actual number keeps changing, and is of less consequence today, than the change in surface temperature that is emphasized in the lead's graphic . —RCraig09 (talk) 02:43, 5 February 2025 (UTC)

in other words, its a political propaganda piece, not an ecyclopedic article. 198.48.146.10 (talk) 16:55, 11 June 2025 (UTC)

@Spearman: If you Google "global surface temperature" and click the "Images" tab, you'll see that the world is interested in the change in temperature since the Industrial Revolution. It's not just this article. FYI: The recent absolute value was 57.0 °F = 13.9 °C, but that's more trivia than important, especially since the temperature keeps changing. See the explanation in the article at Global_surface_temperature#Absolute_temperatures_v._anomalies. —RCraig09 (talk) 18:47, 11 June 2025 (UTC)

I disagree that this article is political propaganda, but I do think that the measured mean temperature at 1900 should be somewhere at the top of this article. As it stands, this article reads to me as "global surface temperature anomaly". I imagine the low-looking number is a target for climate change denial, but it is a good small fact to frame the rest of the article around. BeachEmu (talk) 03:27, 20 November 2025 (UTC)

A glaring omission from the article is the global mean surface temperature. It's defined as an average temperate, which is a number of some units such as degrees Celsius. What is that number? All quantities given are relative to some other unspecified number. Qemist (talk) 09:29, 12 July 2025 (UTC)

@Qemist: See the explanation at the end of the previous section, "What the surface temperature actually is". —RCraig09 (talk) 15:07, 12 July 2025 (UTC)

The fact that it changes does not preclude the inclusion of a well referenced and dated value. Moreover the 1850-1900 reference value is presumably not rapidly changing. If there are uncertainties in its value they should be explained. It remains a strange omission. Qemist (talk) 06:46, 13 July 2025 (UTC)

@Qemist: It is not omitted. Per the above explanation, a particular value is recited in the section titled Global_surface_temperature#Absolute_temperatures_v._anomalies. —RCraig09 (talk) 06:53, 13 July 2025 (UTC)