By Rud Istvan

A sound bite summary*

The climate consensus now has two derogation levels for those who disagree. Climate ‘contrarians’ like Bjørn Lomborg disagree about mitigation policies. Climate ‘deniers’ like Judith Curry disagree about the underlying climatology. The consensus does not any want any disagreement, since their science is ‘settled’ and solutions ‘clear’. They decline to engage (Schmidt/Spencer), disappear comments (Real Climate, the Guardian), refuse to host comments (LATimes), and loudly allege a fossil fuel funded ‘denier’ conspiracy (Grijalva). But they cannot avoid encountering skeptics. Following are some possible skeptical ‘silver bullets’.

There are basic consensus points that most ‘deniers’ “97%” agree with.

· Yes, climate changes. Millennially, we are in the Holocene interglacial, not the preceding ice age. Centennially, we are warming out of the Little Ice Age (LIA); London’s last Thames Ice Fair was in 1814. We are not yet back to Medieval Warm Period (MWP) warmth; Greenland farmers still cannot grow barley as the Vikings did back then.

· Yes, fossil fuels increase atmospheric CO₂ while also greening the planet.

· Yes, CO₂ is a greenhouse gas (GHG), and doubling its atmospheric concentration would by itself cause temperatures to rise between 1.1C and 1.2C (Planck effect given ‘grey Earth’, the most precise estimate using IPCC data being 1.16C).

· Yes, water vapor and clouds (to note only the big two) provide natural feedbacks, which in the case of water vapor must be somewhat positive.

Much more of the ‘settled’ science consensus cannot be correct.

· Erroneous attribution. Observed decadal warming from about 1920 to 1945 cannot be attributed to increasing anthropogenic CO₂ (anthropogentic global warming, AGW) since it didn’t increase very much. The IPCC even said so in AR4WG1 figure SPM.4. Nor can slight cooling from about 1945 to about 1975, since AGW warms. Yet the consensus attributes ‘all’ warming from about 1975 to 2000 to anthropogenic CO₂ (and other GHGs). That cannot be right–natural variability cannot have miraculously ceased in 1975.

· Overly sensitive models. Observed climate sensitivity from about 1880 to now is about half of what climate models estimate (both TCR and ECS). The newest observational estimates are TCR ~ 1.3 and ECS ~ 1.65. CMIP5 mean TCR is 1.8C and the mean ECS is 3.4C; the median ECS is 3.2C. Hot by twice.

· Climate models are now falsified by the 18+ year UAH and RSS ‘pause’, using Santer’s 17 year consensus criterion published in 2011.

· Unsurprisingly, derivative consensus sequelae have also not come true.

· Sea level rise (SLR) is not accelerating. (Most tide gauges are unreliable owing to isostatic adjustment or plate tectonics.) Satellite SLR altimetry since 1979 is higher than differential GPS vertical and motion adjusted long running tide gauges, and does not close (SLR~ sum ice mass loss plus thermosteric rise). DiffGPS adjusted tide gauges do close.

· No historical evidence for a sudden SLR ‘tipping point’ despite previous interglacial (Eemian) temperatures 2 degrees higher for several millennia. No evidence during the Holocene ‘optimum’ caused several millennia ago by Earth’s planetary precession. Papers finding otherwise are flawed, and at least one arguably comprises clear academic misconduct.

· No identifiable potential ice sheet tipping point. Greenland is bowl shaped; nothing can tip. East Antarctica is gaining ice. West Antarctica’s Ronne is stable. ANDRILL proved Ross is anchored, and has not ‘tipped’ before. Amundsen Embayment’s Pine Island and Thwaites glaciers are creeping, not tipping. Even if they did, they are not big enough to matter much. Most of their Amundsen catchment basin is not creeping, and its interior is slowly gaining ice mass.

· Barren ocean ‘acidification’ is half the rate predicted by AR4, since ocean is highly buffered. Fertile ocean pH has much larger seasonal biological swings.

§ -Corals may be in trouble from pollution and overfished reefs, but not from ‘acidification’. The main paper claiming otherwise overlooked toxic hydrogen sulfide, arguably comprising clear academic misconduct.

§ -Pacific oyster spawn at Netarts Bay was not affected by ocean acidification. The hatchery needed to be managed like the estuary it isn’t, where warm summer spawning water is naturally >1.0 higher pH from biological activity. The NOAA PMEL paper claiming otherwise evidences willful negligence (or worse) based on the ‘knew or should have known’ standard.

· Weather extremes are not increasing (cyclones, tornadoes, heat waves).

· Polar bears are thriving thanks to curtailed hunting. No matter what happens to Arctic summer ice, the majority (~80%) of polar bear seal feeding is on spring ice during the whelping season.

· No climate extinctions. CAGW predictions are based on overstated models (like species/areal range S=cA^z), GCMs cannot regionally downscale an A estimate, and endemic species (small initial A) have strong selection bias.

· Consensus mitigation solutions have no answers to contrarian objections.

· Renewables are expensive; that is why they are still heavily subsidized.

· Renewables are intermittent, so must be backed up by equivalent peak gas or spinning reserves prviding grid inertia to keep it stable; that is a large hidden cost beyond direct subsidies. This is why high renewables penetration South Australia suffered a blackout in 2016.

· CCS is much more expensive than nuclear, and (except in special circumstances) geologically impractical. The Kemper Mississippi demonstration plant is a failure both technically and financially. It will burn natural gas; no coal gasification and no CCS.

· Denying inexpensive coal generation to Africa and Asia hurts the neediest, hindering development. China’s new development bank will fund coal stations in Africa and Pakistan, while per consensus mitigation the World Bank won’t. China and India are not playing the UNFCCC COP21 Paris game.

· Lower sensitivity suggests adaptation is sounder than mitigation.

*Drawn partly from ebook Blowing Smoke: Essays on Energy and Climate (example, corals and oysters), and partly from previous WUWT guest posts (example, SLR and closure).