<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE article PUBLIC "-//NLM//DTD Journal Publishing DTD v3.0 20080202//EN" "https://jats.nlm.nih.gov/nlm-dtd/publishing/3.0/journalpublishing3.dtd">
<article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" article-type="research-article" specific-use="SMUR" dtd-version="3.0" xml:lang="en">
<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-2026-4657</article-id>
<title-group>
<article-title>A Post-1998 Transition from Water-Vapor to Joint Greenhouse Gas Forcing regime over Nigeria</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Yusuf</surname>
<given-names>Najib</given-names>
<ext-link>https://orcid.org/0000-0003-1001-4361</ext-link>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Centre for Atmospheric Research, National Space Research and Development Agency, (CAR-NASRDA), Price  Abubakar Audu (PAUU) University Campus, Anyigba, Kogi State. Nigeria</addr-line>
</aff>
<pub-date pub-type="epub">
<day>03</day>
<month>09</month>
<year>2026</year>
</pub-date>
<volume>2026</volume>
<fpage>1</fpage>
<lpage>25</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2026 Najib Yusuf</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-2026-4657/">This article is available from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-4657/</self-uri>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2026/egusphere-2026-4657/egusphere-2026-4657.pdf">The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2026/egusphere-2026-4657/egusphere-2026-4657.pdf</self-uri>
<abstract>
<p>Anthro-forced climatic oscillations across the West African sub-region present severe challenges to regional ecological resilience, yet the fine-scale causal interactions governing localized thermal feedback loops remain elusive. This study bypasses traditional linear constraints by deploying a novel multivariate causality block network tracking architecture to evaluate multi-decadal surface air temperature (SAT) fluctuations across Nigeria. Utilizing a spatially continuous 44-year atmospheric profile from the NASA MERRA-2 reanalysis platform (1981&amp;ndash;2024), this paper maps the evolving coupling between thermodynamic states and localized trace gas mixtures. The causality tracking identifies a profound, systemic regime shift structurally anchored to the historic 1998 climate tipping point. This transition is marked by a sharp SAT anomaly step-change, climbing from a pre-1998 baseline of &amp;minus;0.64 &amp;deg;C to a post-1998 mean of 0.16 &amp;deg;C, coupled with a 66 % expansion in internal thermal variance. While individual trace gas metrics yield weak standalone diagnostic correlations, masking their true impact, non-parametric distributional tracking confirms deep structural divergence across the two temporal eras &lt;em&gt;(p&lt;/em&gt; &amp;lt; 0.001). Crucially, the multivariate network analysis uncovers a fundamental atmospheric paradigm shift: Nigeria&apos;s historical thermal baseline, once regulated by natural water-vapor feedbacks, has transitioned into a highly sensitive, multi-driver configuration. Forecast error variance decomposition demonstrates that contemporary Nigerian SAT shifts are now explicitly driven by a synergistic combination of internal chaotic atmospheric dynamics and joint greenhouse gas forcing. These findings uncover a localized thermodynamic vulnerability, providing an empirical basis for further investigation into the underlying climate mechanisms, spatial heterogeneity, and subcontinental patterns of climate sensitivity and adaptation.</p>
</abstract>
<counts><page-count count="25"/></counts>
</article-meta>
</front>
<body/>
<back>
</back>
</article>