It's just after sunrise, and I'm leaning against the railings of Memorial Drive, which snakes along the Charles River Esplanade in Boston. Rowers move in tandem, back and forth, then gone: leaving behind glistening blue water, framed by old city grandeur rising from the banks above. Joggers pass by on the strip between promenade and road. Despite the activity, there's a striking stillness and serenity on that optimistic autumn morning. Though it's almost November, the scarf and gloves I'd packed before leaving London are redundant. A guilty thought crosses my mind: if this is climate change, then it ain't half bad.