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<front>
<journal-meta>
<journal-id journal-id-type="publisher">EGUsphere</journal-id>
<journal-title-group>
<journal-title>EGUsphere</journal-title>
<abbrev-journal-title abbrev-type="publisher">EGUsphere</abbrev-journal-title>
<abbrev-journal-title abbrev-type="nlm-ta">EGUsphere</abbrev-journal-title>
</journal-title-group>
<issn pub-type="epub"></issn>
<publisher><publisher-name>Copernicus Publications</publisher-name>
<publisher-loc>Göttingen, Germany</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.5194/egusphere-2025-5638</article-id>
<title-group>
<article-title>Decomposing pre-industrial to present-day land use change forcing in the UK Earth System Model</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Sands</surname>
<given-names>Emma</given-names>
<ext-link>https://orcid.org/0009-0008-4204-6767</ext-link>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>O'Connor</surname>
<given-names>Fiona M.</given-names>
<ext-link>https://orcid.org/0000-0003-2893-4828</ext-link>
</name>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Weber</surname>
<given-names>James</given-names>
<ext-link>https://orcid.org/0000-0003-0643-2026</ext-link>
</name>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Doherty</surname>
<given-names>Ruth M.</given-names>
<ext-link>https://orcid.org/0000-0001-7601-2209</ext-link>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Pope</surname>
<given-names>Richard J.</given-names>
</name>
<xref ref-type="aff" rid="aff5">
<sup>5</sup>
</xref>
<xref ref-type="aff" rid="aff6">
<sup>6</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>School of Geosciences, University of Edinburgh, Edinburgh, United Kingdom</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Met Office Hadley Centre, Exeter, United Kingdom</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>Department of Mathematics and Statistics, Global Systems Institute, University of Exeter, Exeter, United Kingdom</addr-line>
</aff>
<aff id="aff4">
<label>4</label>
<addr-line>Department of Meteorology, University of Reading, United Kingdom</addr-line>
</aff>
<aff id="aff5">
<label>5</label>
<addr-line>School of Earth and Environment, University of Leeds, Leeds, United Kingdom</addr-line>
</aff>
<aff id="aff6">
<label>6</label>
<addr-line>National Centre for Earth Observation, University of Leeds, Leeds, United Kingdom</addr-line>
</aff>
<pub-date pub-type="epub">
<day>30</day>
<month>01</month>
<year>2026</year>
</pub-date>
<volume>2026</volume>
<fpage>1</fpage>
<lpage>32</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2026 Emma Sands et al.</copyright-statement>
<copyright-year>2026</copyright-year>
<license license-type="open-access">
<license-p>This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit <ext-link ext-link-type="uri"  xlink:href="https://creativecommons.org/licenses/by/4.0/">https://creativecommons.org/licenses/by/4.0/</ext-link></license-p>
</license>
</permissions>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2026/egusphere-2025-5638/">This article is available from https://egusphere.copernicus.org/preprints/2026/egusphere-2025-5638/</self-uri>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2026/egusphere-2025-5638/egusphere-2025-5638.pdf">The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2026/egusphere-2025-5638/egusphere-2025-5638.pdf</self-uri>
<abstract>
<p>Land use impacts climate through changes in carbon emissions, surface albedo and evapotranspiration, as well as biogenic volatile organic compound (BVOC) emissions, which influence atmospheric composition. The relative importance of changes in atmospheric composition driven by pre-industrial to present-day land use change has not been assessed for the UK Earth System Model (UKESM). Here, we decompose the pre-industrial to present-day land use change forcing in UKESM1.1 with additional process updates. We find a net simulated forcing of &amp;minus;0.08 &amp;plusmn; 0.05 W m&lt;sup&gt;&amp;minus;2&lt;/sup&gt; when using the standard (Strat-Trop vn1.0) chemistry, and &amp;minus;0.12 &amp;plusmn; 0.04 W m&lt;sup&gt;&amp;minus;2&lt;/sup&gt; for the complex (CRI-Strat 2) chemical mechanism. The simulated forcing includes the positive aerosol direct and indirect effects (around +0.06 W m&lt;sup&gt;&amp;minus;2&lt;/sup&gt; and +0.085 W m&lt;sup&gt;&amp;minus;2&lt;/sup&gt;, respectively), alongside negative forcings from ozone (around &amp;minus;0.01 W m&lt;sup&gt;&amp;minus;2&lt;/sup&gt;) and surface albedo change (around &amp;minus;0.17 W m&lt;sup&gt;&amp;minus;2&lt;/sup&gt;). The forcing from the aerosol indirect effects calculated in this study is greater than in recent UKESM BVOC forcing experiments, which we attribute to using pre-industrial background conditions and increased organic matter hygroscopicity. Additional calculations show the radiative forcing from changes to methane lifetime is between &amp;minus;0.02 and &amp;minus;0.04 W m&lt;sup&gt;&amp;minus;2&lt;/sup&gt;, while the land use carbon emissions drive a carbon dioxide forcing of +0.87 W m&lt;sup&gt;&amp;minus;2&lt;/sup&gt;. Overall, the competing effects of changes in aerosols and short-lived greenhouse gases with surface albedo counter around 15 % of the carbon dioxide forcing. However, non-carbon dioxide effects have significant regional impacts.</p>
</abstract>
<counts><page-count count="32"/></counts>
<funding-group>
<award-group id="gs1">
<funding-source>Natural Environment Research Council</funding-source>
<award-id>NE/T00939X/1</award-id>
</award-group>
<award-group id="gs2">
<funding-source>National Centre for Earth Observation</funding-source>
<award-id>NE/R016518/1</award-id>
</award-group>
<award-group id="gs3">
<funding-source>Horizon 2020</funding-source>
<award-id>101003536</award-id>
</award-group>
</funding-group>
</article-meta>
</front>
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