Hurricane Sandy has killed more than 100 people in the U.S. and the Caribbean, and caused billions of dollars in damage. The scene around my Connecticut home is not pretty, with downed trees and power lines everywhere.

It’s a serious time, and a time for some serious questions. Why did this happen? And from a business (or any) perspective, does it matter whether this megastorm was caused by climate change? I’d say no… and yes.

First, the “no” part…

Regardless of the cause, the cost to society of extreme weather has been rising for decades. The insurance giant Munich Re recently released a new report on the rapid increase in weather-related losses. In North America, the number of severe events has quintupled over the last 30 years. And while the report does indeed make the climate change connection directly, on some level it doesn’t really matter for business. The problems and costs of extreme weather are the same either way.

Take the example of one of my clients, a Fortune 200 consumer products company. As the VP of global risk management told me, the most expensive events in company history in every weather category (flood, earthquake, hail, wind, etc.) occurred in the last few years.

After making $50 million in insurance claims in 2011 alone, the company’s insurance rates will certainly rise. But that’s a side issue; the real problem is the constant threat to business continuity. At one of its large manufacturing plants in Asia, a drought stopped production for 3 weeks.

This kind of disruption is only going to grow. In the Thailand floods of November 2011, both the hard-drive industry and the automotive sector experienced serious supply chain problems. As Edmunds reported, car production dropped by 600,000 units and, in particular, “only a few critical Thai-built parts laid Honda low.”

In a deeply unpredictable world, the challenge for multinational businesses is how to build resilient, flexible enterprises that rely on natural resources a great deal less than today (meaning fewer fossil fuels, less water, reduced waste, closed loops on key resources, and so on).

Smart companies will be examining supply chains and operations very closely for risks associated with water shortages, floods, storms, and resource constraints. Risk assessment is going to get much sexier and much more important to global organizations. Their leaders will also seize the opportunity to offer products and services that help other companies and society deal with a world of weird weather. Think drought-resistant crops, new insurance products, distributed energy systems (so homeowners won’t care if the power goes out), and perhaps boats for getting around Wall Street.

OK, now on to the “yes” part of the discussion.

First, the necessary disclaimer: Scientists say that no single storm can be tied to something as large-scale and long-term as climate change (see the active debate going on here). But in the words of NASA scientist James Hansen, we’re “loading the dice” and increasing the odds of extreme events by heating the oceans and putting more moisture into the atmosphere. The devastation around New York City is exactly what was predicted to happen more frequently.

But let’s get real about business impacts. If you’re going to really assess risk to your operations now and in the future, you have to understand how climate change will increase the likelihood of severe events and what it will mean for your value chain. Not doing so would be costly, stupid, and irresponsible to your shareholders.

Companies are waking up to the immediate impacts. The most recent report from the Carbon Disclosure Project (CDP), compiled with the help of PwC (full disclosure: my consulting firm has a partnership with the U.S. arm of PwC), shows that most global companies acknolwedge climate-driven risks.

Fully 37% of those reporting to the CDP - most of the world’s largest companies - say that climate change is already creating business risk (up from 10% in just two years). Another 43% see risk to the business within the next 10 years.

So as companies wake up to this challenge, they are starting to talk about adaptation and the expense of getting ready for a hotter, dryer or wetter (depending on the location), more resource-constrained world. But adapting is just not good enough.

We really have to stop kidding ourselves that we can ride this out. We have to adapt, of course, but we also need to get going on a low-carbon agenda very quickly to mitigate the risk as much as possible.

If you really listen to the scientists, the “business as usual” emissions path were facing over the coming decades could seriously destabilize the planet, which, I hate to state the obvious, supports our economy and way of life. The normal curve of expected possible outcomes is starting to include real risk to our species.

If you bring this level of threat down to the industry or company level, it causes you to rethink your business. As one tech executive said to me recently, “nobody’s really going to care what operating system they have if they don’t have food.” Meaning, we better reduce the odds of disaster or our businesses won’t matter much.

To those of you who fear that the cost of going low carbon will be too high, I have to ask: how expensive are storms like Sandy to business and society? In reality, tackling climate change is not an expense, but a very smart investment. It’s a multitrillion-dollar business opportunity, or what Richard Branson calls “the greatest wealth-generating opportunity of our generation.”

In short, this debate is about direction and speed. In terms of what direction your company should head to prepare for a riskier future of extreme weather, it doesn’t really matter whether Sandy was caused by climate change or not. But how do we determine how fast we need to move in that direction? To answer that question, climate change does truly matter. It matters a lot.