For the first election in decades, climate change did not make an appearance in any of the presidential debates. President Barack Obama and Mitt Romney gave a spirited effort at convincing Americans who would be a better Commander-in-Chief for the challenges we've already been facing. However, the complete absence throughout the debates of any discussion of this truly global threat that requires genuine international action means we have very little sense of who will be the visionary leader for the future.

The moderators of all the debates can share some of the blame for skipping over the issue of global climate change. In truth, though, the moderators did a reasonable job of asking questions that reflected the campaign's major issues, not steering the discourse in new directions. If they didn't ask about the environmental threats our world is facing, it's because nobody - from either side of the two party duopoly - has spent made such themes part of the national conversation.

As a result, American voters won't get to hear the differences between these two candidates - and there are significant differences. Romney's biggest laugh line in his convention address was mocking Obama's 2008 nomination speech for discussing rising sea levels. Throughout the Republican primary, candidates like Romney needed to distance themselves from reasonable, science-based stances to appeal to the Tea Party right.

For their part, the Obama Administration did not make action on carbon reduction a major legislative push, and intervened when its own EPA head tried to take proactive steps. However, from gas mileage improvements in the auto industry to investment in alternative energy, the incumbent showed some willingness to take the right steps. In blocking the Keystone pipeline (at least temporarily) the Administration also gave climate activists hope: there is someone listening in the White House who, with sufficient advocacy, can be convinced.

The American people aren't the only ones who miss out due to the lack of discussion. The global community loses as well. Meaningful action can't come from one country or another - it needs to be a global, integrated approach. It requires allies, compromises and commitment. President Obama embraces those values when discussing nuclear non-proliferation, anti-terrorism or sanctions on Iran. But he - and American - are needed as leaders on climate change. Without America's participation, international action will be weak. Without America's leadership, the necessary international coalition just won't exist.

In discussing the Arab Spring, Iranian posturing, the withdrawal from Iraq and the quagmire in Afghanistan, Obama showed himself a capable and thoughtful leader, and a superior choice to Mitt Romney in facing the challenges of the past few years. He probably also convinced many Americans that he would have been a better commander-in-chief over the past decade, when the Bush/Cheney team engineered a number of the problems the Obama/Biden crew inherited.

The irony, though, is that Obama made a big point in the debate of arguing that he didn't want to be a commander-in-chief for the past, but a leader for the future. His most memorable lines - the now famous "horses and bayonets" as well as the jab that the 1980s were calling and wanted their foreign policy back - lampooned Romney's outdated worldview.

Maybe Romney lives in the distant past, but President Obama needs to be careful not to plant himself in the recent past. Because it's great to have a President with wise hindsight. But we need a leader who also has clear foresight. And without knowing what either man would do to lead the world in combating climate change, the future looks cloudy at best.