Category Archives: Uncategorized

By Nic Lewis

I showed in my May 10th article Why herd immunity to COVID-19 is reached much earlier than thought that inhomogeneity within a population in the susceptibility and in the social-connectivity related infectivity of individuals would reduce, in my view probably very substantially, the herd immunity threshold (HIT), beyond which an epidemic goes into retreat. I opined, based on my modelling, that the HIT probably lay somewhere between 7% and 24%, and that evidence from Stockholm County suggested it was around 17% there, and had been reached. Mounting evidence supports my reasoning.^[1]

I particularly want to highlight an important paper published on July 24th “Herd immunity thresholds estimated from unfolding epidemics” (Aguas et al.).^[2] The author team is much the same as that of the earlier theoretical paper (Gomes et al.^[3]) that prompted my May 10th article. Continue reading →

By Nic Lewis

The course of the COVID-19 pandemic in Sweden is of great interest, as it is one of very few advanced nations where no lockdown order that heavily restricted people’s movements and other basic freedoms was imposed. As there has been much comment, some of it ill-informed, on how the COVID-19 epidemic has developed in Sweden, but relatively little detailed analysis published in English, it is worth exploring what their excellent publicly-available data reveal. Continue reading →

By Nic Lewis

Key points about the recent Nature paper by Flaxman and other Imperial College modellers

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by Roland Hirsch

Mass spectrometry is essential for research in climate science.

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by Judith Curry

Interesting papers that I’ve recently spotted

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By Nic Lewis

Introduction

I showed in my last article that inhomogeneity within a population in the susceptibility and infectivity of individuals would reduce the herd immunity threshold, in my view probably very substantially, and that evidence from Stockholm County appeared to support that view. In this article I will first provide other evidence pointing to such population inhomogeneity being very considerable. I will then go on to consider how the overshoot of infections beyond the herd immunity threshold could be reduced. Continue reading →

By Nic Lewis

The current approach

A study by the COVID-19 Response Team from Imperial College (Ferguson et al. 2020[i]) appears to be largely responsible for driving UK government policy actions. The lockdown imposed in the UK appears, unsurprisingly, to have slowed the growth of COVID-19 infections, and may well soon lead to total active cases declining. However, it comes at huge economic and social costs, and substantial COVID-19-unrelated health costs.

Worse, the lockdown is merely a holding strategy, which offers no long term solution to the COVID-19 problem. The eventual total number of deaths for COVID-19 are not reduced relative to any less restrictive policy that likewise avoided the health system being overwhelmed. Deaths are merely spread over a longer period, assuming that eventually restrictions are lifted and people’s lives return to normal. Continue reading →

By Judith Curry

My latest selection of interesting articles.

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By Nic Lewis

Introduction and summary

A study published two weeks ago by the COVID-19 Response Team from Imperial College (Ferguson20[1]) appears to be largely responsible for driving UK government policy actions. The study is not peer reviewed; indeed, it seems not to have been externally reviewed at all. Moreover, the computer code used to produce the estimates in the study – which on Ferguson’s own admission is old, unverified and documented inadequately, if at all – has still not been published. That, in my view, shows a worrying approach to a matter of vital public concern.

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by Judith Curry

Time for a new thread.

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By Nic Lewis

Introduction

There has been much media coverage about the danger to life posed by the COVID-19 coronavirus pandemic. While it is clearly a serious threat, one should consider whether the best evidence supports the current degree of panic and hence government policy. Much of the concern in the UK resulted from a non-peer reviewed study published by the COVID-19 Response Team from Imperial College (Ferguson et al 2020[1]). In this article, I examine whether data from the Diamond Princess cruise ship – arguably the most useful data set available – support the fatality rate assumptions underlying the Imperial study. I find that it does not do so. The likely fatality rates for age groups from 60 upwards, which account for the vast bulk of projected deaths, appear to be much lower than those in the Ferguson et al. study. Continue reading →

by Judith Curry

A thread devoted to technical topics, e.g. epidemiology, immunology, treatments.  A more general thread will be coming shortly.

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by Judith Curry

Discuss.

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by Frank Bosse

Equilibrium climate sensitivity computed from the latest energy imbalance data.

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by Judith Curry

A few things that caught my eye this past week.

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by Judith Curry

Beto O’Rourke’s Climate Change Plan deserves a close look.

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by Judith Curry

Are all of the ‘worst-case’ climate scenarios and outcomes described in assessment reports, journal publications and the media plausible? Are some of these outcomes impossible? On the other hand, are there unexplored worst-case scenarios that we have missed, that could turn out to be real outcomes? Are there too many unknowns for us to have confidence that we have credibly identified the worst case? What threshold of plausibility or credibility should be used when assessing these extreme scenarios for policy making and risk management?

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by Patrick J. Michaels

We’ve long been fond of showing the satellite evidence for planetary greening caused by increasing carbon dioxide, particularly the work of Zhu et al.(2016):

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by Judith Curry

Countdown to the ‘conversation’ between Mann, Titley, Moore, Curry.  Looks like you can now register for the live broadcast, for a fee of $10 [link].

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By Nic Lewis

Plain language summary

• A new paper by Andrew Dessler et al. claims, based on 100 simulations of the historical period (1850 to date) by the MPI‑ESM1.1 climate model, that estimates of climate sensitivity using the energy-budget method can vary widely due to internal climate system variability.
• I calculated what effect the uncertainty implied by the internal variability affecting the MPI‑ESM1.1 simulations had on the distribution of the primary climate sensitivity estimate in the recent Lewis & Curry energy-budget paper.

• The result was a marginal narrowing of the Lewis & Curry sensitivity estimate. This is because the allowance for internal variability by Lewis & Curry is larger than internal variability in MPI‑ESM1.1.
• Since historical period energy-budget sensitivity estimates are much more  imprecise for other reasons, internal variability contributes little to their total uncertainty; it is an unimportant factor.
• Nothing in the new Dessler et al. paper indicates that the Lewis & Curry energy-budget climate sensitivity estimates are likely to be biased low.

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