v.

double in magnitude, extent, or intensity

"The enemy redoubled their screaming on the radio"

double again

"The noise doubled and redoubled"

make twice as great or intense

"The screaming redoubled"

Union redoubles push for fair evals
Industry redoubles SG increase push
Panasonic's Redoubles Green Efforts
India Redoubles Efforts to Defeat Maoists
Russell redoubles global investment push
US redoubles efforts to increase oil and gas production
U.S. Redoubles Suicide Prevention Efforts in Wake of Surge
Banco Popular redoubles efforts to improve service standards
Global marine yield halved as fishing intensity redoubles
FISH and FISHERIES Global marine yield halved as fishing intensity redoubles