Katharine Hayhoe on Climate Change

Wonderfully balanced, down to earth explanation from Katharine, this should be shared with your friends! This is one of several interviews conducted over at OurBlook, please follow the link back to OurBlook for the rest of the posts in this series.


OurBlook interview with Katharine Hayhoe



In 2007, 489 members of the American Meteorological Society and the American Geophysical Union were surveyed for the Statistical Assessment Service at George Mason University. 84% said that they personally believed human-induced warming is occurring and it poses a very great danger, 74% believed that currently available scientific evidence substantiates its occurrence. Do you agree with the views of these scientists? Why or why not?

KH: Global warming is not something we should "believe" in. Belief, so the Bible tells us, "is the evidence of things not seen." Science, on the other hand, is exactly the opposite of belief. Science is about accumulating the evidence of things that can be seen. And that's what global warming is about.

As scientists, we are trained to question every piece of evidence we are offered. If it holds up, we are then taught to find the explanation that best accounts for the evidence that we are presented with.

So rather than being something that we scientists "believe" in, human-induced global warming is simply the only explanation that can account for the overwhelming number of changes scientists have seen, recorded, and tested. Today, there are more than 25,000 documented records from glaciers, birds, trees, plants, and other "natural thermometers" around the world, all of them pointing towards a rapidly warming world.

Not only that, but all other natural explanations for these changes that have been proposed fail to hold water. For example:

• if our climate were being controlled by the sun right now, as it has been in the past, our world would be cooling--not warming!
• if our temperature change were due to natural cycles internal to the earth's climate system, the whole world wouldn't be heating up, as it is now; rather, we would see some parts of the world getting warmer, while others would be getting cooler.
• if the temperature change was due to urban heating, we would see the greatest warming around cities; whereas in fact, the largest warming is happening over the largely uninhabited expanses of Siberia, Alaska, and northern Canada. (see figures here to illustrate how natural causes fail to explain the warming over the last 50 years: http://www.notbluenotred.com/humans.html )

No, the only explanation that can accurately account for the changes that have been happening in recent decades is the fact that human emissions of heat-trapping gases have been building up in the atmosphere. These gases are artificially increasing the earth's temperature by trapping additional heat that would otherwise escape to space.

Why do you believe that such radically different opinions exist regarding an issue that should ideally be gauged by scientific data?

KH: A recent (2009) study from the University of Illinois-Chicago surveyed active climate researchers as to whether they believed human activity was a significant factor in changing global temperatures. More than 97% of those surveyed replied that they agreed, and the survey concluded, "It seems that the debate on the authenticity of global warming and the role played by human activity is largely non existent amongst those who understand the nuances and scientific basis of long-term climate processes." So in other words, among those familiar with the scientific data, there is little debate regarding the reality of this issue.

This is certainly not the case outside the scientific community, however. It seems that we can turn on the TV and within one minute hear two completely different opinions on climate change, both from people who are convinced they know what they are talking about. Why is that?!

Well, it's hard for anyone not in the field to take the time to wade through the scientific literature on climate: it's often technical, usually boring, and overwhelmingly difficult to decipher. The fact of the matter is that most of us don't have the time to familiarize themselves with the sources of our information on climate change.

Instead, we find ourselves at the mercy of other, much more easily understood communicators: the media, the internet, our colleague next door. And we have no basis for judging which of their opinions may be accurate, and which may be misinformed.

That's why it's very important to examine the legitimacy of our information sources. And on climate change, there are a number of excellent sources to choose from: the U.S. National Academy of Science as well as the national academies of 31 other nations around the world have all issued statements agreeing that climate is changing and humans are primarily responsible for that change. All major scientific organizations whose members include experts in climate science have made similar statements.

Among legitimate sources of information on climate, there is widespread agreement that our climate is changing, that these conditions are highly unusual in the context of the last century and beyond, and that human production of heat-trapping, or greenhouse, gases is primarily to blame for the observed increase in global temperature.

There has been record-breaking cold weather across the northern half of the earth so far in 2010. Do you see greater scientific skepticism toward the global warming concept, greater support building, or about the same?

KH: When we hear something in the news about record cold temperatures, or massive snowstorms, it's tempting to scoff, "So where's that so-called global warming now? I could use a bit of that!"

Here's the truth, though. At the same time that we may be having record snowfalls or cold temperatures, Earth's temperature continues to creep upward. We just don't notice it. That's because weather is very different from climate. They are not one and the same.

Weather is what our minds are designed to remember. It describes conditions from day to day, week to week, and even from year to year.

Weather is that one sweltering week in July, or the coldest November on record, or the snowiest winter ever.

Climate, on the other hand, is nearly impossible for us to remember. It describes the average weather conditions over tens, hundreds, and even thousands of years. Climate is the average temperature or rainfall in a certain place, based on what it's been like for decades.

So it's no wonder, if we aren't aware of the fundamental differences between weather and climate, that some might think that a single cold winter calls into doubt a climate warming that has been happening over decades.

What are your views of the US participating in a multilateral agreement with other countries?

KH: I'm a scientist, not a politician, so my opinion on this question is no more valid than any other layperson. What I do know, however, is that we only have one planet, and we are all depending on this one planet for our future. So it just makes sense to try and figure out the best way to take care of our planet, to ensure a better life for ourselves and our children.

Do you believe that green efforts are necessary or a waste of time?

KH: There are many other good reasons for taking positive action, completely independent of concerns about climate change. By using our resources more efficiently, reducing our reliance on coal, gas and oil, and looking to clean, renewable sources for our energy, we would:

• save money
• clean up our air and water
• reduce our dependence on foreign oil
• invest in our own economy and our people
• preserve our natural resources for future generations

Opportunity lies in every crisis. And here, we have an unparalleled opportunity to re-think the way we live: to transition from the constraints of coal and oil to the freedom of endlessly renewable, homegrown solar and wind energy; to replace outdated, wasteful technologies with the most efficient state-of-the-art alternatives; and to better our environment and, with it, our own welfare as inhabitants of this unique planet. Doesn't that just make sense?

Some experts argue that climate change will hit developing countries the hardest. Regardless of your current opinion), do you believe that first world nations have a responsibility to help those countries?

KH: When we add up each nation's production of heat-trapping gases over the last century, it is obvious that developed or industrialized nations have contributed more than developing nations. The United States alone produced nearly one-third of global emissions from 1900 to 2004.

It is also true that those with fewer resources and who live in more fragile circumstances are most vulnerable to change. Climate change threatens their homes, their livelihoods, and even in some cases their very lives.

And although there are poor and vulnerable in every country, including the United States, more of these people tend to live in developing nations.

These are the facts. In terms of responsibility, each one of us has different values that we use to assign responsibility, so I can't speak to how others should feel in response to these facts.

Personally, however, I believe that God has commanded us to love our neighbor as ourselves. Today, it's the poor, and people who may be strangers to us, who are most vulnerable to harm from climate related impacts. I believe I am called to love my global neighbors as myself; not to simply look the other way, or even worse, perpetuate the idea that this problem is not really happening.

(Katharine Hayhoe is a climate scientist and professor in the Dept. of Geosciences at Texas Tech University. She participated in the Nobel Prize-winning Intergovernmental Panel on Climate Change and served as Lead Author on the definitive report of the U.S. Global Change Research Program, "Global Climate Change Impacts in the United States.")