...aerosols) ' > estimated lo be negative for the put two and possibly me past four decades. Confidence to the ability of models to project future climate has...cannot yet simulate all aspects of climate (eg , they Mill cannot account fully for the obterved tread in the surface-troposphere temperature difference...

...occurred in the periods 1 880 - 1920 and 1960 to 1991. • The combined change in radiative forcing of (he two major natural factors (solar variation and volcanic...four decades. Confidence in the ability of models lo project (tatnre climate has increased, Complex physically-based climate models are required to provide...

...activities. • Natural factors have made small contributions to radiative forcing over the past century. • Confidence in the ability of models to project future climate has increased. • There is new and stronger evidence that most of the wanning observed over the last 50 years is...

...forcing. Natural factors have made small contributions to radiative forcing over the past century. (3) Confidence in the ability of models to project future climate has increased. (4) There is new and stronger evidence that most of the warming observed over the last 50 years is...