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Lighthouse Mobile

· 0 checks — Mobile Lighthouse audit -- Performance, Accessibility, Best Practices, and SEO category breakdown.
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Detailed Report

Audit breakdown by category with detailed findings.

39

Performance

Insights

Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Polyfills and transforms enable older browsers to use new JavaScript features. However, many aren't necessary for modern browsers. Consider modifying your JavaScript build process to not transpile Baseline features, unless you know you must support older browsers. Learn why most sites can deploy ES6+ code without transpiling

Why this matters

Performance issues directly impact user engagement and conversion rates.

3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.

Why this matters

Performance issues directly impact user engagement and conversion rates.

A long cache lifetime can speed up repeat visits to your page. Learn more about caching.

Why this matters

Performance issues directly impact user engagement and conversion rates.

RequestCache TTLTransfer Size
connect.facebook.net/en_US/bundle/sdk.js/1200.0 s77.8 KiB
platform.twitter.com/widgets.js1800.0 s27.3 KiB
www.google-analytics.com/analytics.js7200.0 s20.9 KiB
/jsonp/249617/forms?callback=ml.fn.renderPopupsAndPromotions180.0 s10.0 KiB
/cdn-cgi/challenge-platform/h/b/scripts/jsd/0b8fb825cb67/...14400.0 s13.9 KiB
static.hotjar.com/c/hotjar-2038811.js?sv=560.0 s6.2 KiB
/jsonp/249617/forms/o0QGK8?callback=ml.fn.renderEmbeddedForm180.0 s6.2 KiB
connect.facebook.net/en_US/sdk.js1200.0 s5.0 KiB
static.mailerlite.com/js/w/ml_jQuery.inputmask.bundle.min.js?v3.3.1432000.0 s18.7 KiB
assets.mailerlite.com/js/universal.js432000.0 s14.0 KiB
fonts.mailerlite.com/fonts/s/ptserif/v19/EJRVQgYoZZY2vCFuvAFWzr-_dSb_.woff2432000.0 s13.4 KiB
fonts.mailerlite.com/fonts/s/ptsans/v18/jizfRExUiTo99u79B_mh0O6tLR8a8zI.woff2432000.0 s11.6 KiB
fonts.mailerlite.com/fonts/s/ptsans/v18/jizaRExUiTo99u79D0KExcOPIDU.woff2432000.0 s11.5 KiB
/css?family=Roboto:400,400i,700,700i|Merriweather:400,900...432000.0 s8.2 KiB
groot.mailerlite.com/js/w/webforms.min.js?v2d8fb22bb5b3677f161552cd9e774127432000.0 s4.0 KiB
www.gstatic.com/recaptcha/api2/logo_48.png604800.0 s2.3 KiB
assets.mailerlite.com/css/universal.css432000.0 s673 B
assets.mlcdn.com/fonts.css?version=1730725691200.0 s971 B

Your first network request is the most important. Reduce its latency by avoiding redirects, ensuring a fast server response, and enabling text compression.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Consider setting font-display to swap or optional to ensure text is consistently visible. swap can be further optimized to mitigate layout shifts with font metric overrides.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLEst Savings
cdnjs.cloudflare.com/ajax/libs/font-awesome/5.15.3/webfonts/fa-solid-900.woff265 ms
fonts.mailerlite.com/fonts/s/ptsans/v18/jizaRExUiTo99u79D0KExcOPIDU.woff265 ms
fonts.mailerlite.com/fonts/s/ptserif/v19/EJRVQgYoZZY2vCFuvAFWzr-_dSb_.woff265 ms
fonts.mailerlite.com/fonts/s/ptsans/v18/jizfRExUiTo99u79B_mh0O6tLR8a8zI.woff250 ms
fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff240 ms
fonts.gstatic.com/s/ptsans/v18/jizaRExUiTo99u79D0KExcOPIDU.woff225 ms
fonts.gstatic.com/s/ptsans/v18/jizfRExUiTo99u79B_mh0O6tLR8a8zI.woff225 ms

Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLResource SizeEst Savings
div.col-xs-12 > div.card-featured > picture.thumbnail-wide > img div.col-xs-12 > div.card-featured > picture.thumbnail-wide > img
www.carbonbrief.org/wp-content/uploads/2026/04/3EA5H4F.jpg325.2 KiB313.3 KiB
div.wp-block-group__inner-container > figure.wp-block-image > a > img.wp-image-46547 div.wp-block-group__inner-container > figure.wp-block-image > a > img.wp-image-46547
/wp-content/uploads/2023/06/debriefed-_WEBSITE-INLINE-MOB...108.8 KiB100.5 KiB
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
www.carbonbrief.org/wp-content/uploads/2021/09/hero-5-01-2-300x200.png104.1 KiB94.3 KiB
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
www.carbonbrief.org/wp-content/uploads/2026/04/3CHEK1P-300x199.jpg19.3 KiB17.0 KiB
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
www.carbonbrief.org/wp-content/uploads/2026/04/3E5X202-300x200.jpg17.3 KiB7.5 KiB
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
www.carbonbrief.org/wp-content/uploads/2026/04/R5W2YB-300x200.jpg8.2 KiB6.3 KiB
header > div.logo > a > img header > div.logo > a > img
www.carbonbrief.org/wp-content/themes/carbonbrief/images/logo.png6.8 KiB5.9 KiB
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
www.carbonbrief.org/wp-content/uploads/2026/04/2M0JH57-300x200.jpg13.8 KiB4.1 KiB

Optimize LCP by making the LCP image discoverable from the HTML immediately, and avoiding lazy-loading

Why this matters

Performance issues directly impact user engagement and conversion rates.

lhId: page-0-IMG
nodeLabel: div.col-xs-12 > div.card-featured > picture.thumbnail-wide > img
path: 1,HTML,2,BODY,8,DIV,0,DIV,0,DIV,0,DIV,0,DIV,0,DIV,0,PICTURE,0,IMG
selector: div.col-xs-12 > div.card-featured > picture.thumbnail-wide > img
snippet: <img decoding="async" src="https://www.carbonbrief.org/wp-content/uploads/2026/04/3EA5H4F.jpg">

Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.

Why this matters

Performance issues directly impact user engagement and conversion rates.

description: [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints help the browser establish a connection earlier in the page load, saving time when the first request for that origin is made. The following are the origins that the page preconnected to.
title: Preconnected origins
value: no origins were preconnected
description: Add [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints to your most important origins, but try to use no more than 4.
title: Preconnect candidates

Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLTransfer SizeDuration
/css?family=Roboto:400,400i,700,700i|Merriweather:400,900...8.2 KiB1.0 s
ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/base/jquery-ui.css?ver=6.9.46.2 KiB1.2 s
fonts.googleapis.com/css?family=PT+Serif:400,400italic634 B
fonts.googleapis.com/css?family=PT+Sans:400,700628 B818 ms
assets.mlcdn.com/fonts.css?version=1730725971 B808 ms
fonts.googleapis.com/css?family=PT+Sans+Narrow:400,7001020 B171 ms
cdnjs.cloudflare.com/ajax/libs/font-awesome/5.15.3/css/all.min.css?ver=all10.9 KiB1.3 s
www.carbonbrief.org/wp-includes/js/jquery/jquery.min.js?ver=3.7.130.8 KiB300 ms
/wp-content/plugins/wp-user-avatar/assets/flatpickr/flatp...15.0 KiB150 ms
/wp-content/plugins/wp-user-avatar/assets/select2/select2...19.5 KiB300 ms
www.carbonbrief.org/wp-includes/js/jquery/jquery-migrate.min.js?ver=3.4.15.0 KiB
www.carbonbrief.org/wp-includes/css/dist/block-library/style.min.css?ver=6.9.416.0 KiB450 ms
www.carbonbrief.org/wp-content/tablepress-combined.min.css?ver=1282.1 KiB
www.carbonbrief.org/wp-content/plugins/wp-pagenavi/pagenavi-css.css?ver=2.70322 B
/wp-content/themes/carbonbrief/assets/styles/css/style.cs...7.9 KiB150 ms
/wp-content/plugins/search-filter-pro/public/assets/css/s...6.7 KiB150 ms
/wp-content/themes/carbonbrief/css/theme-gutenberg.css?ve...1.6 KiB
www.carbonbrief.org/wp-content/themes/carbonbrief/css/font-awesome.min.css6.1 KiB300 ms
www.carbonbrief.org/wp-content/themes/carbonbrief/css/bootstrap-datepicker.css2.4 KiB150 ms
www.carbonbrief.org/wp-content/themes/carbonbrief/css/gallery.css941 B
/wp-content/plugins/official-mailerlite-sign-up-forms/ass...367 B
/wp-content/plugins/ml-slider/admin/assets/dist/css/edito...518 B
/wp-content/plugins/wp-user-avatar/assets/flatpickr/flatp...2.7 KiB150 ms
/wp-content/plugins/contact-form-7/includes/css/styles.cs...1.1 KiB150 ms
/wp-content/plugins/wp-user-avatar/assets/select2/select2...2.1 KiB
www.carbonbrief.org/wp-content/themes/carbonbrief/css/theme.min.css13.4 KiB600 ms
/wp-content/plugins/wp-user-avatar/assets/css/frontend.mi...15.1 KiB900 ms
www.carbonbrief.org/wp-content/themes/carbonbrief/css/jquery-fullsizable.css928 B
www.carbonbrief.org/wp-content/themes/carbonbrief/css/responsive.css6.3 KiB300 ms
www.carbonbrief.org/wp-content/themes/carbonbrief/css/bootstrap.min.css20.0 KiB1.2 s
www.carbonbrief.org/wp-content/themes/carbonbrief/css/slick.css597 B
fonts.googleapis.com/css2?family=PT+Sans+Narrow:wght@400;700&display=swap661 B
/css2?family=PT+Serif:ital,wght@0,400;0,700;1,400;1,700&d...753 B
www.carbonbrief.org/wp-content/themes/carbonbrief/css/header-carousel.css1.7 KiB

These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.

Time to Interactive is the amount of time it takes for the page to become fully interactive. Learn more about the Time to Interactive metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

TTI

Redirects introduce additional delays before the page can be loaded. Learn how to avoid page redirects.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 821 ms
URLTime Spent
carbonbrief.org/821 ms
www.carbonbrief.org/0.0 ms

The maximum potential First Input Delay that your users could experience is the duration of the longest task. Learn more about the Maximum Potential First Input Delay metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Diagnostics

Minifying JavaScript files can reduce payload sizes and script parse time. Learn how to minify JavaScript.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 150 ms 12.7 KiB
URLTransfer SizeEst Savings
www.carbonbrief.org/wp-content/themes/carbonbrief/js/moment.js24.9 KiB10.1 KiB
www.carbonbrief.org/wp-content/themes/carbonbrief/js/general.js5.3 KiB2.5 KiB

Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. Learn how to reduce unused CSS.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 1.1 s 72.2 KiB
URLTransfer SizeEst Savings
www.carbonbrief.org/wp-content/themes/carbonbrief/css/bootstrap.min.css19.9 KiB19.3 KiB
www.carbonbrief.org/wp-includes/css/dist/block-library/style.min.css?ver=6.9.415.8 KiB15.7 KiB
/wp-content/plugins/wp-user-avatar/assets/css/frontend.mi...15.0 KiB15.0 KiB
www.carbonbrief.org/wp-content/themes/carbonbrief/css/theme.min.css13.3 KiB12.1 KiB
cdnjs.cloudflare.com/ajax/libs/font-awesome/5.15.3/css/all.min.css?ver=all10.2 KiB10.2 KiB

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 4.2 s 605.6 KiB
URLTransfer SizeEst Savings
www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js361.8 KiB244.4 KiB
www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js361.8 KiB155.8 KiB
www.googletagmanager.com/gtag/js?id=G-R02EV2GBVB162.9 KiB65.0 KiB
connect.facebook.net/en_US/bundle/sdk.js/77.7 KiB53.6 KiB
script.hotjar.com/modules.6a0f3932cb1341a35c18.js56.1 KiB37.8 KiB
platform.twitter.com/widgets.js27.0 KiB26.8 KiB
www.carbonbrief.org/wp-includes/js/jquery/jquery.min.js?ver=3.7.130.7 KiB22.2 KiB

Consider reducing the time spent parsing, compiling, and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to reduce Javascript execution time.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLTotal CPU TimeScript EvaluationScript Parse
www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js1.8 s1.4 s294 ms
Unattributable639 ms5.8 ms0.0 ms
www.carbonbrief.org/527 ms42 ms11 ms
www.carbonbrief.org/cdn-cgi/challenge-platform/scripts/jsd/main.js294 ms212 ms2.1 ms
www.googletagmanager.com/gtag/js?id=G-R02EV2GBVB236 ms180 ms54 ms
platform.twitter.com/widgets.js214 ms144 ms30 ms
www.carbonbrief.org/wp-content/themes/carbonbrief/js/twitter.js119 ms118 ms0.5 ms
script.hotjar.com/modules.6a0f3932cb1341a35c18.js113 ms94 ms17 ms
connect.facebook.net/en_US/bundle/sdk.js/101 ms79 ms22 ms
www.carbonbrief.org/wp-content/themes/carbonbrief/js/jquery.1.11.3.js93 ms63 ms10 ms
www.google-analytics.com/analytics.js74 ms49 ms6.2 ms
www.carbonbrief.org/wp-includes/js/jquery/jquery.min.js?ver=3.7.155 ms39 ms6.3 ms

Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to minimize main-thread work

Why this matters

Performance issues directly impact user engagement and conversion rates.

CategoryTime Spent
Script Evaluation2.7 s
Other787 ms
Script Parsing & Compilation547 ms
Style & Layout423 ms
Parse HTML & CSS169 ms
Garbage Collection91 ms
Rendering26 ms

Minifying CSS files can reduce network payload sizes. Learn how to minify CSS.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 0.0 ms 2.3 KiB
URLTransfer SizeEst Savings
www.carbonbrief.org/wp-content/themes/carbonbrief/css/responsive.css6.3 KiB2.3 KiB

Large network payloads cost users real money and are highly correlated with long load times. Learn how to reduce payload sizes.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLTransfer Size
www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js362.4 KiB
www.gstatic.com/recaptcha/releases/gTpTIWhbKpxADzTzkcabhXN4/recaptcha__en.js361.9 KiB
www.carbonbrief.org/wp-content/uploads/2026/04/3EA5H4F.jpg325.5 KiB
www.googletagmanager.com/gtag/js?id=G-R02EV2GBVB163.1 KiB
platform.twitter.com/embed/embed.9449.78398904051446294e3d.js160.0 KiB
/wp-content/uploads/2023/06/debriefed_WEBSITE-INLINE-768x...141.5 KiB
/wp-content/uploads/2023/06/debriefed-_WEBSITE-INLINE-MOB...109.1 KiB
www.carbonbrief.org/wp-content/uploads/2021/09/hero-5-01-2-300x200.png104.3 KiB
/widgets/widget_iframe.2f70fb173b9000da126c79afe2098f02.h...103.4 KiB
platform.twitter.com/embed/embed.9203.1b3edf1dee6d205547e0.js82.1 KiB

Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensions

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL
div.col-xs-12 > div.card-featured > picture.thumbnail-wide > img div.col-xs-12 > div.card-featured > picture.thumbnail-wide > img
www.carbonbrief.org/wp-content/uploads/2026/04/3EA5H4F.jpg
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
www.carbonbrief.org/wp-content/uploads/2026/04/3CJ2MAG-300x200.jpg
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
www.carbonbrief.org/wp-content/uploads/2026/04/R5W2YB-300x200.jpg
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
www.carbonbrief.org/wp-content/uploads/2026/04/3E88713-300x200.jpg
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
www.carbonbrief.org/wp-content/uploads/2026/04/3E5X202-300x200.jpg
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
www.carbonbrief.org/wp-content/uploads/2026/04/2M0JH57-300x200.jpg
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
www.carbonbrief.org/wp-content/uploads/2026/04/3EA5H4F-300x200.jpg
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
www.carbonbrief.org/wp-content/uploads/2021/09/hero-5-01-2-300x200.png
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
www.carbonbrief.org/wp-content/uploads/2026/04/3CJ2MAG-300x200.jpg
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
www.carbonbrief.org/wp-content/uploads/2026/04/3CHEK1P-300x199.jpg
header > div.logo > a > img header > div.logo > a > img
www.carbonbrief.org/wp-content/themes/carbonbrief/images/logo.png
div.row > div.col-md-5 > div.ftrLogo > img div.row > div.col-md-5 > div.ftrLogo > img
www.carbonbrief.org/wp-content/themes/carbonbrief/images/logoFtr.png

More information about the performance of your application. These numbers don't directly affect the Performance score.

●Layout shift culprits
●Optimize DOM size
●Forced reflow
●LCP breakdown
●Modern HTTP
●Optimize viewport for mobile
●User Timing marks and measures 5 user timings
●Avoid long main-thread tasks 20 long tasks found
●Page didn't prevent back/forward cache restoration
●Network Requests
●Network Round Trip Times 30 ms
●Server Backend Latencies 460 ms
●Tasks
●Diagnostics
●Metrics
●Screenshot Thumbnails
●Final Screenshot
●Script Treemap Data
●Resources Summary
●Initial server response time was short Root document took 50 ms
○INP breakdown
○Avoid non-composited animations
○Avoid large layout shifts
81

Accessibility

These checks highlight opportunities to improve the accessibility of your web app. Automatic detection can only detect a subset of issues and does not guarantee the accessibility of your web app, so manual testing is also encouraged.

Names and labels

Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more about the `alt` attribute.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
body#topBack > header > figure.mobile-menu-toggle > img body#topBack > header > figure.mobile-menu-toggle > img
div.col-xs-12 > div.card-featured > picture.thumbnail-wide > img div.col-xs-12 > div.card-featured > picture.thumbnail-wide > img
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img

Form elements without effective labels can create frustrating experiences for screen reader users. Learn more about the `select` element.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
All Types Articles Daily Brief ul > li.sf-field-post_type > label > select.sf-input-select
All Items 1.5C Antarctic Arctic Attribution Carbon budgets China Briefing China… ul > li.sf-field-category > label > select.sf-input-select
Sort Results By Title (Deecending) Title (Ascending) ul > li.sf-field-sort_order > label > select.sf-input-select

Link text (and alternate text for images, when used as links) that is discernible, unique, and focusable improves the navigation experience for screen reader users. Learn how to make links accessible.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
body#topBack > header > div.logo > a body#topBack > header > div.logo > a
header > nav.rightMenu > div.topSrc > a header > nav.rightMenu > div.topSrc > a
div.col-xs-12 > div.card > picture.thumbnail-wide > a div.col-xs-12 > div.card > picture.thumbnail-wide > a
div.col-xs-12 > div.card > picture.thumbnail-wide > a div.col-xs-12 > div.card > picture.thumbnail-wide > a
div.col-xs-12 > div.card > picture.thumbnail-wide > a div.col-xs-12 > div.card > picture.thumbnail-wide > a
div.col-xs-12 > div.card > picture.thumbnail-wide > a div.col-xs-12 > div.card > picture.thumbnail-wide > a
div.wp-block-group > div.wp-block-group__inner-container > figure.wp-block-image > a div.wp-block-group > div.wp-block-group__inner-container > figure.wp-block-image > a
div.col-xs-12 > div.card > picture.thumbnail-wide > a div.col-xs-12 > div.card > picture.thumbnail-wide > a
div.col-xs-12 > div.card > picture.thumbnail-wide > a div.col-xs-12 > div.card > picture.thumbnail-wide > a
div.col-xs-12 > div.card > picture.thumbnail-wide > a div.col-xs-12 > div.card > picture.thumbnail-wide > a
div.col-xs-12 > div.card > picture.thumbnail-wide > a div.col-xs-12 > div.card > picture.thumbnail-wide > a
div.col-xs-12 > div.card > picture.thumbnail-wide > a div.col-xs-12 > div.card > picture.thumbnail-wide > a
div.row > div.col-xs-12 > p.text-header > a.text-header div.row > div.col-xs-12 > p.text-header > a.text-header
footer > div.container > div.backTop > a footer > div.container > div.backTop > a
body#topBack > footer > div.ftrSM > a body#topBack > footer > div.ftrSM > a
body#topBack > footer > div.ftrSM > a body#topBack > footer > div.ftrSM > a
body#topBack > footer > div.ftrSM > a body#topBack > footer > div.ftrSM > a
body#topBack > footer > div.ftrSM > a body#topBack > footer > div.ftrSM > a

These are opportunities to improve the semantics of the controls in your application. This may enhance the experience for users of assistive technology, like a screen reader.

Best practices

Disabling zooming is problematic for users with low vision who rely on screen magnification to properly see the contents of a web page. Learn more about the viewport meta tag.

Why this matters

Informational: a Permissions-Policy directive showing feature -> allowed origins.

Source: MDN Permissions-Policy

Failing Elements
head > meta head > meta

One main landmark helps screen reader users navigate a web page. Learn more about landmarks.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
html html

These items highlight common accessibility best practices.

○Interactive controls are keyboard focusable
○Interactive elements indicate their purpose and state
○The page has a logical tab order
○Visual order on the page follows DOM order
○User focus is not accidentally trapped in a region
○The user's focus is directed to new content added to the page
○HTML5 landmark elements are used to improve navigation
○Offscreen content is hidden from assistive technology
○Custom controls have associated labels
○Custom controls have ARIA roles
●`[aria-*]` attributes match their roles
●`[aria-hidden="true"]` is not present on the document `<body>`
●`[role]`s have all required `[aria-*]` attributes
●`[role]` values are valid
●`[aria-*]` attributes have valid values
●`[aria-*]` attributes are valid and not misspelled
●Input buttons have discernible text.
●Form elements have associated labels
●ARIA attributes are used as specified for the element's role
●`[aria-hidden="true"]` elements do not contain focusable descendents
●Elements use only permitted ARIA attributes
●Background and foreground colors have a sufficient contrast ratio
●Document has a `<title>` element
●`<frame>` or `<iframe>` elements have a title
●`<html>` element has a `[lang]` attribute
●`<html>` element has a valid value for its `[lang]` attribute
●Links are distinguishable without relying on color.
●Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).
●List items (`<li>`) are contained within `<ul>`, `<ol>` or `<menu>` parent elements
●Touch targets have sufficient size and spacing.
●Heading elements appear in a sequentially-descending order
●Deprecated ARIA roles were not used
●Identical links have the same purpose.
○`[accesskey]` values are unique
○`button`, `link`, and `menuitem` elements have accessible names
○Elements with `role="dialog"` or `role="alertdialog"` have accessible names.
○ARIA input fields have accessible names
○ARIA `meter` elements have accessible names
○ARIA `progressbar` elements have accessible names
○Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.
○`[role]`s are contained by their required parent element
○Elements with the `role=text` attribute do not have focusable descendents.
○ARIA toggle fields have accessible names
○ARIA `tooltip` elements have accessible names
○ARIA `treeitem` elements have accessible names
○Buttons have an accessible name
○The page contains a heading, skip link, or landmark region
○`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.
○Definition list items are wrapped in `<dl>` elements
○ARIA IDs are unique
○No form fields have multiple labels
○`<html>` element has an `[xml:lang]` attribute with the same base language as the `[lang]` attribute.
○`<input type="image">` elements have `[alt]` text
○The document does not use `<meta http-equiv="refresh">`
○`<object>` elements have alternate text
○Skip links are focusable.
○No element has a `[tabindex]` value greater than 0
○Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.
○`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe.
○`[lang]` attributes have a valid value
○`<video>` elements contain a `<track>` element with `[kind="captions"]`
○Tables have different content in the summary attribute and `<caption>`.
○All heading elements contain content.
○Uses ARIA roles only on compatible elements
○Image elements do not have `[alt]` attributes that are redundant text.
○Elements with visible text labels have matching accessible names.
○Tables use `<caption>` instead of cells with the `[colspan]` attribute to indicate a caption.
○`<td>` elements in a large `<table>` have one or more table headers.
81

Best Practices

General

Deprecated APIs will eventually be removed from the browser. Learn more about deprecated APIs.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Deprecation / WarningSource
SharedStorage
www.carbonbrief.org/cdn-cgi/challenge-platform/scripts/jsd/main.js
StorageType.persistent is deprecated. Please use standardized navigator.storage instead.
www.carbonbrief.org/cdn-cgi/challenge-platform/scripts/jsd/main.js
Fledge
www.carbonbrief.org/cdn-cgi/challenge-platform/scripts/jsd/main.js
●Uses HTTPS
●Avoids third-party cookies
●Allows users to paste into input fields
●Avoids requesting the geolocation permission on page load
●Avoids requesting the notification permission on page load
●Displays images with correct aspect ratio
●Serves images with appropriate resolution
●Page has the HTML doctype
●Properly defines charset
●No browser errors logged to the console
●No issues in the `Issues` panel in Chrome Devtools
●Ensure CSP is effective against XSS attacks
●Use a strong HSTS policy
●Ensure proper origin isolation with COOP
●Mitigate clickjacking with XFO or CSP
●Mitigate DOM-based XSS with Trusted Types
●Detected JavaScript libraries
●Page has valid source maps
○Redirects HTTP traffic to HTTPS
85

SEO

These checks ensure that your page is following basic search engine optimization advice. There are many additional factors Lighthouse does not score here that may affect your search ranking, including performance on Core Web Vitals. Learn more about Google Search Essentials.

Content Best Practices

Descriptive link text helps search engines understand your content. Learn how to make links more accessible.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Link destinationLink Text
www.carbonbrief.org/science/See more
www.carbonbrief.org/science/See more
www.carbonbrief.org/policy/See more
www.carbonbrief.org/policy/See more
www.carbonbrief.org/nature/See more
www.carbonbrief.org/nature/See more
www.carbonbrief.org/nature/See more
www.carbonbrief.org/nature/See more
www.carbonbrief.org/in-focus/See more
www.carbonbrief.org/in-focus/See more

Informative elements should aim for short, descriptive alternate text. Decorative elements can be ignored with an empty alt attribute. Learn more about the `alt` attribute.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
body#topBack > header > figure.mobile-menu-toggle > img body#topBack > header > figure.mobile-menu-toggle > img
div.col-xs-12 > div.card-featured > picture.thumbnail-wide > img div.col-xs-12 > div.card-featured > picture.thumbnail-wide > img
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img
div.card > picture.thumbnail-wide > a > img div.card > picture.thumbnail-wide > a > img

Format your HTML in a way that enables crawlers to better understand your app’s content.

○Structured data is valid
●Page isn’t blocked from indexing
●Document has a `<title>` element
●Document has a meta description
●Page has successful HTTP status code
●Links are crawlable
●robots.txt is valid
●Document has a valid `hreflang`
●Document has a valid `rel=canonical`

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