BARCELONA, Spain — Spain must do more to prepare for increasingly virulent wildfires stoked by climate change, a large group of the country’s leading wildfire prevention experts said on Thursday. A declaration backed by 60 experts and institutions said the “increasingly intense fires … are producing unprecedented ecological and social consequences.” The experts concluded that Spanish society must come to terms with the emergencies that it will likely face, given that wildfires in increasingly hot and dry conditions in the Iberian Peninsula are often “beyond the capability (of firefighters) to extinguish” with their own means. The declaration was the outcome of a two-day meeting in Madrid in March organized by the Pau Costa Foundation, a nonprofit group based in Barcelona that works for fire prevention awareness.