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-	<h1>Cement and its emissions<h2>
+	<h1>Cement and its emissions</h1>
+	<p>Concrete is said to be the second-most used substance in the world, after water, and the glue that binds concrete together is cement. Producing cement results in substantial emissions of CO<span class="subb">2</span>, both from the use of fossil fuels, but also, and in fact more importantly, from the chemical process itself. Cement is made from limestone (CaCO<span class="subb">3</span>), which when heated results in lime (CaO) and CO<span class="subb">2</span>. Global emissions datasets usually quantify emissions from fossil fuels first and then add in other categories, so it's important to have a good estimate of these process emissions from cement production.</p>
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 	<h2>Global cement process emissions</h1>
 	<p>As part of the Global Carbon Budget fossil CO<span class="subb">2</span> dataset, I produce an independent dataset of the global emissions from production of cement clinker. These are the so-called "process" emissions, which result from the decomposition of carbonates (particularly limestone), and are separate from the use of fossil fuels.</p>
 	<p>The dataset is archived on the Zenodo permanent European science data repository <a href="https://doi.org/10.5281/zenodo.831454">here</a>.</p>