base period compares with long-term trends and might affect the budget estimates’, the IPCC says.73 As a specific temperature limit is approached, ‘relative uncertainties become larger’.74 The remaining budget is affected both by uncertainties in past greenhouse gas emissions and estimates of the proportion of warming that is human-induced, the IPCC says. ‘As a result, only medium confidence can be assigned to the assessed remaining budget values for 1.5°C and 2°C and their uncertainty’.75 Medium confidence? The whole edifice of the 1.5°C net zero emissions trajectory and timetable has been erected on a foundation in which the IPCC itself expresses only medium confidence. Based on the modest confidence it has in its own data and analysis, the IPCC asserts with high confidence that net carbon dioxide emissions must decline by about 45% from the 2010 level of 49 GtCO2e by 2030, and reach net zero by around 2050.76 The steep drop to 2030 is now steeper than implied by the IPCC. According to the UN Environment Programme, greenhouse gas emissions (including land-use change) grew at 1.3% a year in the decade to 2018, to 55.3 GtCO2equivalent.77 A 45% reduction from 2010 levels would require a reduction of 22 GtCO2e, to 27 GtCO2e. Emissions growth since then means the 22 GtCO2e reduction is now a 28 GtCO2e reduction and a 45% reduction has become a 51% reduction.
6.
Holes in IPCC climate science
‘The science says…’ is a statement oft repeated by politicians and climate activists, as if climate scientists descend from Mount Sinai bearing tablets of stone inscribed with the commandments for our planetary future. As we’ve just seen, estimates of future warming and remaining carbon budgets are manufactured and involve the subjective choices and judgments of climate scientists. In a critical review of the 1.5 special report for the GWPF, Professor J Ray Bates, adjunct professor of meteorology in the Meteorology and Climate Centre at University College Dublin, raises additional criticisms over and above those made by Nic Lewis: The IPCC does not discuss satellite-observed temperature trends, which show a warming trend of only 0.13°C per decade in the period 1979–2018, nor ask why they differ markedly from surface trends. A statistical analysis in which the prominent El Niño signal in the period 2000–16 is removed from the record finds the remaining warming trend is of the order of only 0.04°C per decade.78 From 1900 to 1980, observed land and sea surface temperatures rose and fell at the same rate over multi-decadal periods. From 1980, a strong divergence appears, with land temperatures rising much faster than sea surface temperatures. Why? Though consistent with greenhouse-induced warming, the much weaker rise in sea-surface temperature does not unambiguously exceed the 18
