Hottersummers could result in more insects and parasites that prey on the caribou, which could then also reduce the annual caribou harvest by local indigenous peoples.
Melting glaciers, hottersummers and migrations of plants, animals and even deadly microbes have convinced virtually every climate scientist on earth that human activity has indeed started to warm the planet.
When we see that actually recent summers are on average hotter than earlier summers then we might start to think about trends, not just the variance that comes from more data.
Greenery is critical to counterbalance the "urban heat island" effect from hotter, drier summers, when night-time temperatures remain high because of heat retained by brick and tarmac.