"Life in the Hothouse: How a Living Planet Survives Climate Change" is author Melanie Lenart's call to global warming sanity. A journalist-turned-scientist (she holds a Ph.D. in natural resources and global change), Lenart informs and educates the lay reader about not only what global warming is (she goes over the basics of the science and the history of the movement), but how it will affect the climate — and us — in the future. Working from the analogy that a warming Earth is like a sweaty person, as the Earth heats, the natural reaction will be to attempt to cool itself, in the form of more and more severe hurricanes, rising seas and floods. Lenart's straightforward but ultimately anthropocentric narrative style puts the human back into human-caused climate change.

MNN: You weave personal narrative and “real person experiences” into the science and research details in "Life in the Hothouse"; did you feel that too much of the global warming writing out there was unrelatable to the average person?

Lenart: There are some excellent books out there on global warming, but not enough that really touch people — in a sensory way. People want to engage their senses when reading — what does it look like, how does it smell, do you feel a breeze?

Computer models of climate change projections just do not lend themselves to that experience. That’s partly why I focus on things we can imagine seeing and feeling — the six-foot-long leaves you can find in the humid tropics, how dust whipped through the chill winds of the ice ages.

Many of the things we know about climate can make sense to anyone who has lived through different seasons, or tossed and turned their way through a humid night. I hope that showing this more tangible side of climate can help people understand at a deeper level that we are talking about a reality that has existed before and could return to haunt us again if we don’t get a handle on our greenhouse gases.

It’s interesting that few books have drawn their lessons from past climates and the differences between existing hot and cold climates that we can see and feel. It turns out this evidence, these observations from the past, generally support the projections for temperature rise that the computer models make. At the same time, they give us a more believable baseline about how plant life responds to warmer climates, because there’s still a long way to go on computer modeling of how life responds to changing conditions.

Who do you hope your audience is, or who did you write the book for?

I wrote this book for concerned people, including environmentalists, who are really worried about the state of the planet — especially the people who are afraid that we’re about to obliterate Spaceship Earth and all its crew, including us. I hope they can find some comfort in the thought that the planet has been through hot times before, hothouses when no ice at all covered the planet. Life made it through, although not always smoothly.

I also wrote it for people who want to go beyond global climate model projections. A close look at how the planet fared during past hothouses and warm periods makes it clear that we humans would face tremendous problems with even a slight warming, much less some of the numbers we are talking about for later this century. Forests might survive in many places they exist today, and perhaps even expand in others — but these changes still often involve fire and other die-offs along the way. Storms and hurricanes might help cool the warmest parts of the planet, but they still do tremendous damage when they strike cities. Heat waves, drought, floods that are off the charts, such as what we’ve seen in Pakistan and, for that matter, Rhode Island — these are the types of problems that come with changing climate.

I’ve been pleasantly surprised to see some interest in the book among sectors that often are more skeptical of climate change. Several radio show hosts on conservative stations interviewed me about the book, saying something to the effect of, “I’m fiscally conservative, but we only have one planet.” I find hope in that. It makes me feel that if people on all sides of the political spectrum understand that we are talking about major problems here, maybe we could rally to do something about it. The argument that a planetary warming is OK because it’s happened before doesn’t hold up. Life continued during these hothouses, but sea levels were some 200 feet higher than they are now. That’s because temperatures were so high that the ice at both poles melted. Greenhouse gas levels were much higher than our currents levels — but sometimes within the range of future projections for these gas levels. Sure, the greenhouse gases during these hothouses came from natural sources, such as volcanoes or undersea methane pockets. This time around, we’re the ones releasing the greenhouse gases by burning coal, oil, gas and forests. So? The effect is the same.

It became clear to me in writing this book that the planet has particular “sweet spots” when it comes to temperature. Almost like water has three phases — ice, liquid and steam — the planet seems to have three relatively stable climate phases: ice ages, warm interglacials like our current climate, and steamy hothouses. People who complain about the humidity in our current climate phase would not appreciate one of the hothouses where the Earth seemed to be facing drippy, tropical heat from its equator to its poles. We just don’t know with enough precision when the climate might reach a tipping point that carries it into another state of existence.

As you point out in the hurricanes chapter, the Earth's reaction to warming, in the form of tropical storms, is messy and somewhat destructive to the natural world, but most of all, to human beings and the trappings of our civilization. In your view, is stopping or slowing global warming more about preventing bad things from happening to us rather than some amorphous concept of “saving the planet”?

If polar bears could read, I’d write more about the many problems they face. Ditto other species. But, as you note, there are plenty of problems we humans face from this ongoing climate shift — and not just the people in poor countries, either. Storms, heat waves, droughts, floods, fires — all of these can become more extreme as temperatures rise. Shifting agriculture, too, is a problem that can affect us all, hitting some of us in the wallet and others in the stomach. Individuals, including our friends and relatives, will be the ones suffering from the specific events. Yet we all stand to incur monetary damages. As taxpayers, we all feel the pain when a major city faces a disaster made worse by changing climate. These past few years have made it clear how vulnerable our national and even global economy is to instability. Huge risks, economic and otherwise, are associated with ignoring climate change.

People care about what happens to people, so I focus on that. Still, many of the things we do to make our own lives easier on the climate change front will also benefit a multitude of other species and keep the planet itself healthy. This is true of any actions we take to reduce our fossil fuel use, as individuals and as a country, and anything we do to protect and/or allow the expansion of forests and wetlands. Not only do these natural systems help moderate the temperature rise; for the most part, they also provide services that become more important as the planet heats up, such as providing shade, cleaning water, blocking wind, and harboring species, including animals such as shrimp that we like to eat. People are an important part of the big picture, especially because we’re the ones with our fingers on the power switches.

The subtitle of your book is "How a Living Planet Survives Climate Change"; do you see this change as inevitable? Do you think individual changes (driving and flying less, eating a vegetarian diet, and using less energy to heat/cool our homes) are more important, or societal/governmental ones?

We need to do everything we can to keep the ongoing changes at a manageable level, and that means efforts by government, private companies and individuals. Everybody counts. Climate change has already begun. The roughly 1 degree Fahrenheit rise we’ve seen in the 20th century has led, just since 1997, to the 10 hottest years in the instrumental record globally.

Controlling our greenhouse gas emissions is key. Government needs to provide incentives to support solar and wind energy, which our country has begun to recognize. These incentives help balance out the government subsidies for fossil fuels to give renewable energy sources a fair starting point. They need a boost. Individual people are thrilled when solar panels, for instance, become affordable. So they’ll contribute to the effort as government and private businesses make solar power more affordable. Everybody wins.

But along with reducing our fossil fuel use, we need to take other actions as well, as individuals and at the government level, to keep the planet healthy and society stable. In the book, I tend to emphasize the role of plants in helping us to keep the temperature in a manageable range. At the government level, that might mean placing a monetary value on the protection of forests and wetlands, especially coastal wetlands because they do not emit the greenhouse gas methane.

Government agencies also could support projects to thin smaller trees out of some western U.S. forests to make them more resilient to fire and drought. For individuals, this could mean planting shade trees in their yards, or working with their cities to plant more streetside trees or leave areas around rivers undeveloped. The movement toward growing food locally can occur in backyards or community gardens, and helps keep people healthy while reducing the need to use gas to transport food across the country.

Government can also support good science. The value of vegetation needs to be explored in more detail — but in realistic ways. I am concerned that people are taking too seriously the results of experimental computer models that project future destruction of major forest systems, such as in the Amazon. Should we be concerned about these systems? Of course. But on-the-ground studies and experiments are essential to help us gauge the risks.

What's your take on the people who agree that global warming's happening, but who say we should continue unfettered growth and just deal with the consequences of climate change with technological solutions?

There's support for so-called “geoengineering” ideas — such as blocking incoming sunlight by adding more pollution to the air or by placing screens in orbit. These geoengineering ideas, while well-intentioned, could lead to big problems, such as an increase in drought. An increase in land-based shade from trees is far more time-tested. Forests and wetlands have been in place for hundreds of millions of years.

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