Melting ice, protesters, sun dimming: how well do you know this week's climate news?

Seven questions on Antarctic ice, the Brussels climate march, El Niño, sun-dimming, data centres and Lake Balaton – based on fresh news.

1. How low was this year's Antarctic sea-ice maximum extent in the satellite record?
2. Roughly how large was the Antarctic sea-ice peak extent on 14 September?
3. Ahead of which summit did tens of thousands march in Brussels on Sunday demanding stronger climate action?
4. Whose water was warmer in September than ever before, pointing to a worrying El Niño outlook?
5. Whose geopolitical risks did experts and former officials test in a London war-game?
6. Which resources does the US data-centre building boom strain, according to Foreign Policy?
7. What tool could protect Lake Balaton's remaining natural shoreline from development?