At dinner following BSR’s Board meeting in London last month, discussion turned quickly to the potential for a looming crash in global markets (no, sadly, this is not a post from 2008). Round and round we went, debating whether the sovereign and consumer debt levels weighing down Europe and the United States were precursors to another crash in the global financial system.

Unfortunately, the three weeks since then have only deepened these concerns. The Euro mess is not only ensnaring Italy, Spain, and Portugal but also is starting to cause banks to restrict their lending. Again, this is so very 2008. In the United States, the follies over the debt ceiling have now become so all encompassing that the government in Washington seemingly is unable to focus on anything else.

This is all quite worrying, and indeed, there is likely a better chance for a new economic meltdown than any time in the past three years. Rupert Murdoch is not the only one having a bad week.

But frankly, pessimism is not something we can afford. These challenging times must be about creativity and leadership.

If Washington is consumed with debating whether to make good on past debts, then business needs to remind us why investing in the future is our only hope.

If consumers remain sluggish and under siege, then businesses need to enlist consumers in the war on waste, which seems perfectly suited for lean times, when all of us have to do more with less.

And as I wrote in a recent post, periods of economic uncertainty tend to produce great innovations, and the challenge of creating low-carbon prosperity for nine billion people is the great challenge of our time.

There is another reason why all the pessimism may not be warranted. It is certainly true that stagnation may be with us to stay in the Western economies. But the plain fact is that we are stagnating at levels of prosperity unknown in human history. The average middle-class person in the United States or Europe has comforts, abilities, and, yes, things that only the richest segment of society was able to claim—or imagine—50 years ago.

While this doesn’t erase the fears that stalk people who worry about losing their jobs or erase the pressure on companies to meet market expectations, it is important context for us all to remember.

The impact of this is simple: We have much to lose if we let the sustainability agenda fall behind even—especially when times are hard. We also have more ability to invest in a future than we think we do. If we let pessimism rule the day, a bleak future becomes a self-fulfilling prophecy. There’s no reason why that needs to be the case.