{"id":23309,"date":"2013-09-30T09:54:29","date_gmt":"2013-09-30T15:54:29","guid":{"rendered":"http:\/\/rankexploits.com\/musings\/?p=23309"},"modified":"2013-09-30T10:34:30","modified_gmt":"2013-09-30T16:34:30","slug":"ar5-wg1-final-draft","status":"publish","type":"post","link":"https:\/\/rankexploits.com\/musings\/2013\/ar5-wg1-final-draft\/","title":{"rendered":"AR5 WG1: Final Draft"},"content":{"rendered":"

I guess this is all but the copy\/typo editing version.
\nhttp:\/\/www.climatechange2013.org\/report\/review-drafts\/<\/a><\/p>\n

Chapter 9<\/p>\n

Although the forcing uncertainties are substantial, there are no apparent incorrect or missing global-mean forcings in the CMIP5 models over the last 15 years that could explain the model\u00e2\u20ac\u201cobservations difference during the warming hiatus.<\/p><\/blockquote>\n

The discrepancy between simulated and observed GMST trends during 1998\u00e2\u20ac\u201c2012 could be explained in part by a tendency for some CMIP5 models to simulate stronger warming in response to increases in greenhouse-gas concentration than is consistent with observations (Section 10.3.1.1.3, Figure 10.4). Averaged over the ensembles of models assessed in Section 10.3.1.1.3, the best-estimate greenhouse-gas (GHG) and other anthropogenic (OA) scaling factors are less than one (though not significantly so, Figure 10.4), indicating that the model-mean GHG and OA responses should be scaled down to best
\nmatch observations. This finding provides evidence that some CMIP5 models show a larger response to greenhouse gases and other anthropogenic factors (dominated by the effects of aerosols) than the real world (medium confidence). As a consequence, it is argued in Chapter 11 that near-term model projections of GMST increase should be scaled down by about 10% (Section 11.3.6.3). This downward scaling is, however, not sufficient to explain the model-mean overestimate of GMST trend over the hiatus period<\/em><\/p><\/blockquote>\n

[…]<\/p>\n

Note: The italicized agrees with what I’ve been saying. \ud83d\ude42 <\/p>\n

In summary, the observed recent warming hiatus, defined as the reduction in GMST trend during 1998\u00e2\u20ac\u201c2012 as compared to the trend during 1951\u00e2\u20ac\u201c2012, is attributable in roughly equal measure to a cooling contribution from internal variability and a reduced trend in external forcing (expert judgment, medium confidence). The forcing trend reduction is primarily due to a negative forcing trend from both volcanic
\neruptions and the downward phase of the solar cycle. However, there is low confidence in quantifying the role of forcing trend in causing the hiatus, because of uncertainty in the magnitude of the volcanic forcing trend and low confidence in the aerosol forcing trend.<\/p><\/blockquote>\n

[…]<\/p>\n

A prediction!! \ud83d\ude42 <\/p>\n

The causes of both the observed GMST trend hiatus and of the model\u00e2\u20ac\u201cobservation GMST trend difference during 1998\u00e2\u20ac\u201c2012 imply that, barring a major volcanic eruption, most 15-year GMST trends in the near-term future will be larger than during 1998\u00e2\u20ac\u201c2012 (high confidence; see 11.3.6.3. for a full assessment of near-term
\nprojections of GMST). The reasons for this implication are fourfold: first, anthropogenic greenhouse-gas concentrations are expected to rise further in all RCP scenarios; second, anthropogenic aerosol concentration is expected to decline in all RCP scenarios, and so is the resulting cooling effect; third, the trend in solar forcing is expected to be larger over most near-term 15\u00e2\u20ac\u201cyear periods than over 1998\u00e2\u20ac\u201c2012 (medium confidence), because 1998\u00e2\u20ac\u201c2012 contained the full downward phase of the solar cycle; and fourth, it is more likely than not that internal climate variability in the near-term will enhance and not counteract the surface warming expected to arise from the increasing anthropogenic forcing.<\/p><\/blockquote>\n

Note: I do expect warming trends to increase. But predicting that the trends will turn up is not the same as predicting they will catch up to the AR5 trends (and note: the IPCC isn’t even necessarily predicting they will catch up to AR5 trends.)<\/p>\n

[…]<\/p>\n

Here, by contrast, internal variability is characterised through the width of the model ensemble.<\/p><\/blockquote>\n

No matter how many times they use it and no matter how favorably they cite papers that use it, if they are using a multi-model ensemble, the ‘width of the model ensemble’ is a utterly bogus<\/b> estimate of internal variability. It includes (a) spread due to internal variability in models and (b) spread due to structural uncertainty. At best (a) is an estimate of internal variability; (b) has absolutely nothing to do with internal variability. <\/p>\n","protected":false},"excerpt":{"rendered":"

I guess this is all but the copy\/typo editing version. http:\/\/www.climatechange2013.org\/report\/review-drafts\/ Chapter 9 Although the forcing uncertainties are substantial, there are no apparent incorrect or missing global-mean forcings in the CMIP5 models over the last 15 years that could explain the model\u00e2\u20ac\u201cobservations difference during the warming hiatus. The discrepancy between simulated and observed GMST trends … Continue reading AR5 WG1: Final Draft<\/span> →<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[15],"tags":[],"class_list":["post-23309","post","type-post","status-publish","format-standard","hentry","category-data-comparisons"],"_links":{"self":[{"href":"https:\/\/rankexploits.com\/musings\/wp-json\/wp\/v2\/posts\/23309","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/rankexploits.com\/musings\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/rankexploits.com\/musings\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/rankexploits.com\/musings\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/rankexploits.com\/musings\/wp-json\/wp\/v2\/comments?post=23309"}],"version-history":[{"count":0,"href":"https:\/\/rankexploits.com\/musings\/wp-json\/wp\/v2\/posts\/23309\/revisions"}],"wp:attachment":[{"href":"https:\/\/rankexploits.com\/musings\/wp-json\/wp\/v2\/media?parent=23309"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/rankexploits.com\/musings\/wp-json\/wp\/v2\/categories?post=23309"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/rankexploits.com\/musings\/wp-json\/wp\/v2\/tags?post=23309"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}