evidence: But it's still far too early to say whether their approach can actually make a difference to the rapid decline in Arctic sea-ice. [...] The Arctic Ocean is likely to be effectively free of sea-ice by the end of summer at least once by 2050, and possibly even sooner. As the graph below shows, it's already experienced steep declines since the 1980s. [...] "We have to reduce emissions, but even if we do them as quickly as possible, the Arctic is still going to melt."