  The Sun's activity cycle governs the radiation, particle and magnetic flux in
the heliosphere creating hazardous space weather. Decadal-scale variations
define space climate and force the Earth's atmosphere. However, predicting the
solar cycle is challenging. Current understanding indicates a short window for
prediction best achieved at previous cycle minima. Utilizing magnetic field
evolution models for the Sun's surface and interior we perform the first
century-scale, data-driven simulations of solar activity and present a scheme
for extending the prediction window to a decade. Our ensemble forecast
indicates cycle 25 would be similar or slightly stronger than the current cycle
and peak around 2024. Sunspot cycle 25 may thus reverse the substantial
weakening trend in solar activity which has led to speculation of an imminent
Maunder-like grand minimum and cooling global climate. Our simulations
demonstrate fluctuation in the tilt angle distribution of sunspots is the
dominant mechanism responsible for solar cycle variability.
