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Figure 2.Climate and immunity correlations with annual state WNND cases.

The effect of (a) immunity (cumulative incidence; coeff. = -2.05, F1,300 = 96.42, p < 0.001), (b) precipitation (coeff. = -0.0009, F1,161 = 2.20, p = 0.14), (c) drought (coeff. = -0.14, F1,274 = 27.01, p < 0.001), (d) winter severity (coeff. = -0.05, F1,34 = 2.95, p = 0.09), (e) temperature (PIP: coeff. = 0.06, F1,276 = 2.58, p = 0.10; TAR: coeff. = 0.22, F1,144 = 53.59, p < 0.001; QUI: coeff. = 0.002, F1,104 = 0.0005, p = 0.98) and (f) temperature modelled as the relative R0 value at a given temperature (coeff. = 1.66, F1,121 = 17.33, p < 0.001) on the total logged number of WNND cases (adjusted for state random effects) in a given state and year (1999–2013). In (ad,f), the filled red points and fitted lines are univariate regressions for states in which that predictor was significant (a < 0.05), while open black points depict states in which the predictor was not significant. In (e), green crosses, blue circles and green triangles denote states where C. tarsalis, C. pipiens and C. quinquefasciatus, respectively, dominate transmission and the relationship is only significant for C. tarsalis. (Online version in colour.)
Figure 3.Climate, immunity and WNND cases.

(a) Yearly WNND cases and fitted model (line) in nine representative states, and projections of the number of future cases under mean (M) or extreme (E—95th percentile) climate conditions for either current (cross-hatch) or future (star) climate projections. Error bars include both the standard error of the mean projected values and the standard deviation of the residuals between current projected and actual values. (b) Colours/shading indicate the significant variables in the fitted models by state with pie-charts showing their relative importance. (c) Human WNND cases and abundance of infected mosquitoes in Colorado when all humans were naive (2003, filled points, coeff = 0.99, F1,175 = 173.1, p < 0.001) and in subsequent years (2004–2008, open points, coeff = 0.72, F1,787 = 285.5, p < 0.001). Variables were power transformed (1/4) to equalize leverage and linearize the relationship. (Online version in colour.)
Keeping the Temperature Rise to 1.5° C

"If Covid-19 leads to a drop in emissions of around 5% in 2020, then that is the sort of reduction we need every year until net-zero emissions are reached around 2050," said Glen Peters, also from Cicero. "Such emissions reductions will not happen via lockdowns and restrictions, but by climate policies that lead to the deployment of clean technologies and reductions in demand for energy." Energy experts believe there will be a bounce back next year, but that, long term, the world will move to greener fuels.
Table 2.2 | The assessed remaining carbon budget and its uncertainties.

Shaded blue horizontal bands illustrate the uncertainty in historical temperature increase from the 1850–1900 base period until the 2006–2015 period as estimated from global near-surface air temperatures, which impacts the additional arming until a specific temperature limit like 1.5°C or 2°C relative to the 1850–1900 period. Shaded grey cells indicate values for when historical temperature increase is estimated from a blend of near-surface air temperatures over land and sea ice regions and sea-surface temperatures over oceans.