On Thursday, the mercury hit 100 degrees in Moscow, the hottest day since record-keeping began in 1880; it was the fourth day in a week that the city set a temperature record. Highs for July and August typically average in the low-to-mid 70s.

The heat stoked wildfires that continue to burn out of control and have overwhelmed the country’s firefighters, while an unparalleled drought withered crops so severely that Prime Minister Vladimir V. Putin took the radical step of banning all grain exports. Smoke from the fires has turned the Moscow air into a thick, toxic soup.

Russia’s president, Dmitri A. Medvedev, blamed the crisis on climate change and called for action.

“What’s happening with the planet’s climate right now needs to be a wake-up call to all of us, meaning all heads of state, all heads of social organizations, in order to take a more energetic approach to countering the global changes to the climate,” Mr. Medvedev said recently