Editing IPCC:AR6/SRCCL/Chapter-2 (section)

==== 2.2.1.1 Climate drivers of land form and function ====

<div id="section-2-2-1-1-climate-drivers-of-land-form-and-function-block-1"></div>

Energy is redistributed from the warm equator to the colder poles through large-scale atmospheric and oceanic processes driving the Earth’s weather and climate (Oort and Peixóto 1983 <sup>[[#fn:r26|26]]</sup> ; Carissimo et al. 1985 <sup>[[#fn:r27|27]]</sup> ; Yang et al. 2015a <sup>[[#fn:r28|28]]</sup> ). Subsequently, a number of global climate zones have been classified ranging from large-scale primary climate zones (tropical, sub-tropical, temperate, sub-polar, polar) to much higher-resolution, regional climate zones (e.g., the Köppen-Geiger classification, Kottek et al. 2006 <sup>[[#fn:r29|29]]</sup> ). Biomes are adapted to regional climates (Figure 2.1) and may shift as climate, land surface characteristics (e.g., geomorphology, hydrology), CO <sub>2</sub> fertilisation and fire interact. These biomes and the processes therein are subject to modes of natural variability in the ocean-atmosphere system that result in regionally wetter/dryer or hotter/cooler periods having temporal scales from weeks to months (e.g., Southern Annular Mode), months to seasons (e.g., Madden-Julian Oscillation), years (e.g., El Niño Southern Oscillation) and decades (e.g., Pacific Decadal Oscillation). Furthermore, climate and weather extremes (such as drought, heatwaves, very heavy rainfall, strong winds), whose frequency, intensity and duration are often a function of large-scale modes of variability, impact ecosystems at various space and timescales.

It is ''very likely'' that changes to natural climate variability as a result of global warming has and will continue to impact terrestrial ecosystems with subsequent impacts on land processes (Hulme et al. 1999 <sup>[[#fn:r30|30]]</sup> ; Parmesan and Yohe 2003 <sup>[[#fn:r31|31]]</sup> ; Di Lorenzo et al. 2008 <sup>[[#fn:r32|32]]</sup> ; Kløve et al. 2014 <sup>[[#fn:r33|33]]</sup> ; Berg et al. 2015 <sup>[[#fn:r34|34]]</sup> ; Lemordant et al. 2016 <sup>[[#fn:r35|35]]</sup> ; Pecl et al. 2017 <sup>[[#fn:r36|36]]</sup> ). This chapter assesses climate variability and change, particularly extreme weather and climate, in the context of desertification, land degradation, food security and terrestrial ecosystems more generally. This section does specifically assess the impacts of climate variability and climate change on desertification, land degradation and food security as these impacts are assessed respectively in Chapters 3, 4 and 5. This chapter begins with an assessment of observed warming on land.

<div id="section-2-2-1-1-climate-drivers-of-land-form-and-function-block-2"></div>

<span id="figure-2.1"></span>
<!-- START IMG -->
<!-- IMG TITLE -->
'''Figure 2.1'''

<span id="worldwide-bioclimatic-classification-system-19962018.source-rivas-martinez-et-al.-2011.-online-at-www.globalbioclimatics.org"></span>
<!-- IMG CAPTION -->
'''Worldwide Bioclimatic Classification System, 1996–2018.Source: Rivas-Martinez et al. (2011). Online at www.globalbioclimatics.org'''
<!-- IMG FILE -->
[[File:6bb2aee1284046e6e1b0ccde2455bf3e Figure-2.1-1024x504.png]]

Worldwide Bioclimatic Classification System, 1996–2018.Source: Rivas-Martinez et al. (2011). Online at [[IPCC:Srccl:Chapter:Chapter-2:Www.globalbioclimatics.org|www.globalbioclimatics.org]]

<!-- END IMG -->
<div id="section-2-2-1-2-changes-in-global-land-surface-air-temperature"></div>

<span id="changes-in-global-land-surface-air-temperature"></span>