The climatic effects of climate engineering—or geoengineering—via cirrus cloud thinning are examined. Thinner cirrus clouds can allowmore outgoing longwave radiation to escape to space, potentially cooling the climate. The cloud properties and climatic effects due to perturbing the ice crystal fall speed are investigated in a set of hemispheric scale sensitivity experiments with the Community E...

The observed global warming of the past century occurred primarily in two distinct 20-year periods, from 1925 to 1944 and from 1978 to the present. Although the latter warming is often attributed to a human-induced increase of greenhouse gases, causes of the earlier warming are less clear because this period precedes the time of strongest increases in human-induced greenhouse gas (radiative) fo...

The forcing theorem is the most fundamental result about set forcing, stating that the forcing relation for any set forcing is definable and that the truth lemma holds, that is everything that holds in a generic extension is forced by a condition in the relevant generic filter. We show that both the definability (and, in fact, even the amenability) of the forcing relation and the truth lemma ca...

[1] Radiative forcing is a useful tool for predicting equilibrium global temperature change. However, it is not so useful for predicting global precipitation changes, as changes in precipitation strongly depend on the climate change mechanism and how it perturbs the atmospheric and surface energy budgets. Here a suite of climate model experiments and radiative transfer calculations are used to ...

Carbonaceous aerosols (CA) emitted by fossil and biomass fuels consist of black carbon (BC), a strong absorber of solar radiation, and organic matter (OM). OM scatters as well as absorbs solar radiation. The absorbing component of OM, which is ignored in most climate models, is referred to as brown carbon (BrC). Model estimates of the global CA radiative forcing range from 0 to 0.7 Wm(-2), to b...

Abstract We consider embedded, smooth curves in the plane which are either closed or asymptotic to two lines. study their behaviour under curve shortening flow with a global forcing term. prove an analogue Huisken’s distance comparison principle for initial whose local total curvature does not lie below $$-\pi $$ -</mm...