Editing IPCC:AR6/WGI/Chapter-4 (section)

=== FAQ 4.3 | At a Given Level of Global Warming, What Are the Spatial Patterns of Climate Change? ===

<div id="h2-29-siblings" class="h2-siblings"></div>

<div id="faq-4-3"></div>

As the planet warms, climate change does not unfold uniformly across the globe, but some patterns of regional change show clear, direct and consistent relationships to increases in global surface temperature. The Arctic warms more than other regions, land areas warm more than the ocean surface, and the Northern Hemisphere more than the Southern Hemisphere. Precipitation increases over high latitudes, tropics and large parts of the monsoon regions, but decreases over the subtropics. For cases like these, we can infer the direction and magnitude of some regional changes – particularly temperature and precipitation changes – for any given level of global warming.

The intensity of climate change will depend on the level of global warming. It is possible to identify certain patterns of regional climate change that occur consistently, but increase in amplitude, across increasing levels of global warming. Such robust spatial patterns of climate change are largely independent of the specific scenario (and pathway in time) that results in a given level of global warming. That is, as long as different scenarios result in the same global warming level, irrespective of the time when this level is attained in each scenario, we can infer the patterns of regional change that would result from this warming. When patterns of changes are robust, regional consequences can be assessed for all levels of global warming, for all future time periods, and for all scenarios. Temperature and precipitation show such robust patterns of changes that are particularly striking.

The high latitudes of the Northern Hemisphere are projected to warm the most, by two to four times the level of global warming – a phenomenon referred to as Arctic amplification (FAQ 4.3, Figure 1, left). Several processes contribute to this high rate of warming, including increases in the absorption of solar radiation due to the loss of reflective sea ice and snow in a warmer world. In the Southern Hemisphere, Antarctica is projected to warm faster than the mid-latitude Southern Ocean, but the Southern Hemisphere high latitudes are projected to warm at a reduced amplitude compared to the level of global warming (FAQ 4.3, Figure 1, left). An important reason for the relatively slower warming of the Southern Hemisphere high latitudes is the upwelling of Antarctic deep waters that drives a large surface heat uptake in the Southern Ocean.

The warming is generally stronger over land than over the ocean, and in the Northern Hemisphere compared to the Southern Hemisphere, and with less warming over the central subpolar North Atlantic and the southernmost Pacific. The differences are the result of several factors, including differences in how land and ocean areas absorb and retain heat, the fact that there is more land area in the Northern Hemisphere than in the Southern Hemisphere, and the influence of ocean circulation. In the Southern Hemisphere, robust patterns of relatively high warming are projected for subtropical South America, southern Africa, and Australia. The relatively strong warming in subtropical southern Africa arises from strong interactions between soil moisture and temperature and from increased solar radiation as a consequence of enhanced subsidence.

Precipitation changes are also proportional to the level of global warming (FAQ 4.3, Figure 1, right), although uncertainties are larger than for the temperature change. In the high latitudes of both the Southern and Northern Hemispheres, increases in precipitation are expected as the planet continues to warm, with larger changes expected at higher levels of global warming (FAQ 4.3, Figure 1, right). The same holds true for the projected precipitation increases over the tropics and large parts of the monsoon regions. General drying is expected over the subtropical regions, particularly over the Mediterranean, southern Africa and parts of Australia, South America, and south-west North America, as well as over the subtropical Atlantic and parts of the subtropical Indian and Pacific Oceans. Increases in precipitation over the tropics and decreases over the subtropics amplify with higher levels of global warming.

Some regions that are already dry and warm, such as southern Africa and the Mediterranean, are expected to become progressively drier and drastically warmer at higher levels of global warming.

In summary, climate change will not affect all the parts of the globe evenly. Rather, distinct regional patterns of temperature and precipitation change can be identified, and these changes are projected to amplify as the level of global warming increases.

[[File:d732fedae99bb1e06fbf5376c2f0e7d5 IPCC_AR6_WGI_FAQ_4_3_Figure_1.png]]

'''FAQ 4.3, Figure 1''' '''|''' '''Regional changes in temperature (left) and precipitation (right) are proportional to the level of global warming, irrespective of the scenario through which the level of global warming is reached.''' Surface warming and precipitation change are shown relative to the 1850–1900 climate, and for time periods over which the globally averaged surface warming is 1.5°C '''(top)''' and 3°C '''(bottom)''' , respectively. Changes presented here are based on 31 CMIP6 models using the high-emissions scenario SSP3-7.0.

<div id="references" class="h1-container"></div>