Climate change explored by William Chameides

On May 12, 2011, the U.S. National Research Council – part of the National Academies – released a final report on a series of studies called America’s Climate Choices. The U.S. Congress requested this work, asking for science-based recommendations on what – if anything – should be done about climate change. The National Research Council recommendations (pdf) are straightforward: limit emissions of heat-trapping gases such as CO2, while adapting to a climate that is already changing. EarthSky’s Jorge Salazar spoke with Bill Chameides, vice chairman of the Committee on America’s Climate Choices.

What are the main findings of the final report on America’s Climate Choices?

With inputs from hundreds of experts, we confirmed that global warming is, in fact, occurring. It is very likely due to human activities. The risks that we face as a result of global warming are quite significant.

We spent about two years in this study, in a time when much of climate science was being questioned in the media and in political arenas. We had input from scientists, economists and political leaders on both sides of the aisle, leaders in the private sector, and community leaders. On this basis, we felt that the risks are so severe that it warrants urgent action – both to limit the emissions of global warming gases as well as to adapt to climate change.

Our other finding is that the best way to address these problems is through a process that we call risk management. We’ll never know exactly what’s going to happen in the future. So we should adopt a process that assesses the risks, develops options for addressing those risks, and is flexible. Those options, and how we apply them, might need to be changed as we learn more about the climate.

What are the risks from climate change?

First, water issues. You might be facing instances where you don’t have enough water, and where you have droughts. You might also be facing instances where you have floods. Some parts of the United States might actually experience – from year to year – one or the other. And we’re already seeing that occurring in parts of Texas and Oklahoma, in fact.

We can expect to see impacts on agricultural production.

We can expect to see greater heat waves, and subsequent health effects from heat waves.

A major effect in the coming decades is sea level rise, and the impact of sea level rise on greater storm intensity on coastlines and on flooding.

We think we’re already seeing the impacts of climate change on things such as storm intensity and heat waves. It’s very difficult to establish that with a great level of certainty. It’s even harder to say what’s going to happen in the future. The future is uncertain. We’ll never have perfect knowledge of what’s going to happen next year, ten years, or 20 years from now.

The public focus is on how certain we are, with the underlying assumption that we shouldn’t act until we know for sure. The fact is, we’re never going to know for sure. And just like when the waters rise at the river, and you’re worried about a flood, you don’t wait until the experts tell you exactly how high the water’s going to rise. You go out and get some sand bags and develop evacuation plans.

We’re seeing changes in climate that we’re pretty darn sure are due to human activities. And we think they’re going to get worse. They can ultimately be quite severe, in terms of droughts and crop failures.

It’s time to begin to act on those, on trying to limit those risks.

Tell us about the evidence. Where did you get your information?

We had inputs from hundreds of scientists and experts. We started with a summit, where we invited experts from around the world to tell us what they knew about climate. And we then went off and did our own investigations, looked at the literature, and – on the basis of all that – came to our conclusions.

It’s clear that the globe is warming. We have temperature records. We have melting ice. We have changes in seasons – earlier springs and later falls.

Meanwhile, some of the most fundamental physics we have is telling us human activities are impacting the climate. A law of thermodynamics is about conservation of energy. If the atmosphere is heating up, extra energy is coming from somewhere. And over the past several decades, scientists have been trying to identify where that extra energy is coming from. We know now that it’s not coming from the sun, because we’ve been measuring the output from the sun for decades. We know it’s not coming from the ocean. In fact, the oceans are heating up. And after searching, and searching, and searching, the only thing we’re left with is that it’s coming from these extra greenhouse gases we’re putting into the atmosphere.

The U.S. Congress requested the America’s Climate Choices report. What should be done right now, or very soon, about climate change?

There are two really, really important parts of our response to climate change. One is what we call mitigation or limiting. We need to start taking action as quickly as possible to lower heat-trapping gaseous emissions into the atmosphere.

The other really important part is about adapting to climate change. The climate is already changing. Even if we were to cut increases in emissions today to zero, we would still be seeing continuing climate change and warming. We’re going to have to begin to adapt to those.

Our committee recommends an iterative risk management approach, which allows us to continue to adjust our targets when things change in the future.

Sounds like self-correcting trial-and-error instead of trying to decide on the goal right away.

Absolutely. We’re going to be working on this problem for decades. Exactly where we need to end up, decades from now, is not exactly clear. But we’re definitely not going to get there if we don’t get started.

So let’s just understand that we have a big job ahead of us, and get started, and allow ourselves to figure out exactly where we’re going to end up as the future unfolds and as the climate changes.

Give us a good example on how the U.S. can get started on taking action on climate change.

There are a number of things that are already being discussed – like renewable portfolio standards. Many of the states are developing their own climate programs.

We think, long term, the most effective way to get a handle on lowering emissions is to put a price on carbon. If we can send a signal to the marketplace, and to people, that there’s going to be a cost associated with polluting the atmosphere, we and many economists believe that entrepreneurs, business people and corporations will begin to invest in new technologies to save money – in fact, to make money – by emitting less carbon. We call that a low carbon economy.

What should the U.S. do about climate in the long run?

It’s not clear that climate change caused by greenhouse gas emissions isn’t already having significant impacts on important issues like water and floods, and so on. It’s just very, very hard to pinpoint that impact. So that’s number one.

It’s also important to recognize that the emissions that we put into the atmosphere today aren’t going to fully manifest themselves for decades. But once they manifest themselves, they’re going to be around for generations – a thousand years, perhaps.

So deciding to not act today is to establish that the world is going to have to deal with those emissions for many, many, many years.

If we put in policies to address this issue and it turns out that – for whatever reason – it’s not nearly as bad as we thought, we can reverse those policies. You can’t reverse climate changes. And that’s why I think we need to take this proactive risk management approach that begins to recognize that we have risks, doesn’t commit us to exactly what we’re going to be doing in the future, but gets us started down the road of avoiding those risks.

What’s the most important thing you want people today to know about America’s Climate Choices?

I want them to know is that it is about choices. We face risks. And as Americans, as a society, we have to make choices about what we’re going to do about those risks. And doing nothing now is a choice. Our committee, and the people we’ve spoken to for the most part, feel that doing nothing is a very risky and imprudent choice. A much more prudent choice is to begin acting now to address the risks of climate change.

Risk of impact from climate change is growing, says NRC report

William Chameides blog: The Green Grok