THE MONTH OF AUGUST has flown by. Summer is almost over. It’s hard to believe that Julie and Tom have to go home to Boston at the end of this week. I’ve gotten used to having them here with me, and will be sad to see them go.

Earlier this month the children’s dad and mom joined us for two weeks. The late-summer days were sunny and warm, with light winds and very little rain. Tom and his dad spent a lot time of bass fishing, sometimes motoring out through the opening from Pleasant Bay into the Atlantic Ocean to fish in the deep water.

Route From the Narrows to the Ocean

I joined them on one of those ocean fishing trips. We left very early, an hour before sunrise. Not a ripple showed on the surface of the bay as we swooped along the narrow channels and past the sandy point that marks the entrance to the ocean. Tom stood up forward, steadying himself by holding the bow line. I marveled at his confidence, and how much he seemed to have grown in just the past eight weeks.

Once we were far enough offshore, Tom’s dad turned off the engine and we sat quietly, watching for signs of fish. A brightening red glow in the east signaled dawn. Suddenly Tom straightened up and pointed ahead.

“There!” he said sharply. “See the bait fish jumping out of the water?” He grabbed his spinning rod and prepared to cast. His dad started the boat and we slipped quietly forward. As we approached, several bass rolled through the surface not ten yards away.

In an instant Tom’s cast was away. His lure had hardly hit the water when the tip of his rod was yanked down and line began screaming off his reel. “I’ve got one!” he grunted, clinging to the handle.

“Let it run. We’ll follow it with the boat!” said his dad, shifting the engine into gear. Soon the fish began to tire, and Tom was able to take in line. I found the landing net and moved beside him, ready to help land his catch. When the bass got close enough to see the boat, it turned and darted away again. “Whoa!” Tom said, as line was stripped from his reel.

“Remember to keep your rod tip up!” his dad reminded him.

Soon Tom was able to guide the tiring fish next to the boat, where I could slip the net under it and hoist it aboard. Tom stood quietly, looking at the bass quivering on the bottom of the boat. He seemed a bit surprised at his success. Then he smiled and high-fived his dad and me.

“It’s big enough to keep,” I pointed out. “Do you want to bring it home for dinner?”

Tom glanced at his dad as I removed the lure from the fish’s lip. “Naw, I guess not.”

“Okay, you can release it back into the water,” his dad said. “Make sure you wet your hands first, so you won’t mess up the slime on the fish’s body. The slime protects it from diseases.”

Tom dipped his hands into the water, then reached into the net. With one hand around the bass’s narrow tail and the other under its big belly, he lifted it over the side of the boat. Gently he eased the fish into the water, moving it back and forth to get water and oxygen into its gills.

After a few seconds it twitched its tail strongly and swam out of Tom’s hands, down into the dark green depths of the sea. Tom sighed deeply and smiled. “Now that was cool!”

Over the next half hour we caught and released several more. But once the orange orb of the sun climbed up out of the sea, the bass dove deep and were gone. So we motored home, arriving just in time for breakfast.

WHEN HALEY AND GEORGE left in July, Julie asked me to teach her how to sail. “Will you take me out in your catboat so I can learn?” she asked. (My boat is called a catboat because it turns as quick as a cat.)

I love sailing, so she didn’t need to ask twice.

“Sure,” I answered, “but first let’s see what we can learn on dry land.” Using a toy sailboat, we talked about how to steer when the wind comes from different directions. Julie also learned the names of important parts of the boat, like the bow (front), the stern (back), the boom (extends out from the mast and carries the sail), and the tiller (what we use to steer the boat).

The Basic Working Parts of a Catboat

The next morning a nice gentle wind was blowing, so we went out for our first real lesson. Julie steered and I took care of the sail. She quickly discovered how to use the tiller. “I get it,” she said after a few tries. “If you want the sailboat to turn to the right, then you have to push the tiller to the left. To go left you push it to the right!”

Once we were out in the bay, we wanted to go in the direction that the wind was coming from. Julie soon realized we couldn’t sail directly into the wind, because then the wind couldn’t fill the sail and it would just flap.

“If we want to go someplace that’s exactly upwind of where we are, I have to zigzag back and forth to get there, right?” she asked.

“That’s right,” I replied. “It’s called tacking.” Soon she learned to point the sailboat a little to the right or to the left of where the wind was coming from. That way the wind would hit the sail from the side and push the boat forward.

“I just watch the sail and steer so it doesn’t flap, up there near the mast,” she explained. She eased the tiller carefully to port (left) so that the sail stretched out taut, full of wind.

When it was time to sail back toward home, with the wind behind us, Julie steered the boat around in a half circle. “Now I can point the boat straight at where we want to go because the wind is right behind us!” she proclaimed.

We were whooshing along pretty fast now. I let the sail out until the boom was sticking straight out from the side of the boat, so the following wind would fill it completely. “Be careful!” I yelled when Julie forgot to steer straight ahead. “If you let the wind get on the wrong side of the sail, the boom will come crashing across the boat, and we could get hurt!”

Julie was startled but steered very carefully all the way home.

By the time the kids’ parents joined us, Julie was becoming a good sailor. She even took them out in my catboat to show them what she had learned. They sailed for almost an hour in a gentle breeze while I watched from the beach.

When they sailed back to the beach, Julie was still at the tiller, her smile stretching from ear to ear. “We had a great sail!” she announced as the bow crunched gently up on the sand. Her mom looked very happy to be back but told Julie, “You did great!” And her dad gave her a big hug.

THIS MORNING we’re in the kitchen, just finishing up our scrambled eggs on toast. It’s Tom and Julie’s last day on the Cape this summer, and I’m feeling a little down because I won’t be seeing them every day.

“Are you looking forward to getting home and starting school?” I ask.

Julie swallows her last bit of egg. “Kind of,” she answers. “It’s gonna be nice to see all my friends again. Soccer will be fun, too.”

“You’ll be in a new school, right? How does that feel?” Julie is moving on to middle school.

“I’m sort of nervous. But Tom will be there, and that might help. I hope I like my teachers.”

“You will.” Tom takes a long gulp of orange juice. “The sixth-grade teachers are really nice.”

“What about you, Gas Guy—are you excited about your last year in middle school?”

“Pretty much.” Tom runs his hand absently through his crewcut. “It’ll be nice to be the oldest kids in the school for a change. And I’m really looking forward to my science class.”

“Oh?” I pour myself another cup of coffee. “What kind of science do you have this year?”

Tom has been examining the big toe of his right foot, which he cut on a sharp shell. “Earth science,” he answers with real enthusiasm, straightening up. “The cool thing is that we’ll be studying all the things we talked about this summer, like Gaia!”

“Like what exactly, Tom?” Julie asks.

Tom thinks for a minute. “Well, like the different layers of the Earth, with the crust and the mantle, and how the plates move around and bump into each other. I think it’s called plate tectonics. And we study the atmosphere at lot, so I’m gonna do well on that part, too.”

I ask Tom what he thinks is the most important thing he’s learned about the atmosphere this summer.

Tom doesn’t hesitate. “Carbon,” he says. “Carbon in the atmosphere, and where it comes from.”

“Okay, so where does carbon come from?” We haven’t talked about Gaia and her organs for almost a month, and I wonder how much Tom remembers.

“Remember the carbon cycle?” He heads into my study, returning with my laptop. “I saved that picture that shows it.”

The “Extra Carbon” Cycle

The green arrows show the natural carbon cycle. The dark gray arrows show the extra carbon cycle, which happens when we burn gas, oil, and coal.

Tom brings it up on the screen and leads us through the cycle again, starting with photosynthesis in trees and other plants.

“Everything’s okay in the little cycle, where we breathe in oxygen and breathe out carbon dioxide,” he explains. “The problem is over here” —he points to a house and a lawnmower— “where we humans burn fossil fuels, the oil and gas and coal.”

Julie isn’t sure why using gas and oil is a problem. “We need to heat our house to stay warm, Tom,” she argues. “What’s wrong with that?”

Tom sighs. The worry lines in his forehead signal that he’s been thinking hard about this. “The trouble is, all the extra carbon from burning so much gas and oil gets caught in our atmosphere. The carbon dioxide gas gets trapped.”

Julie stretches her tanned legs out. “Oh, right,” she says. “The blanket around the Earth that keeps us warm but not too warm. I thought that blanket keeps the Earth just right—like Goldilocks and the porridge.”

Tom pops up out of his chair and walks to the open window, watching the birds on the bird feeder. After a minute he turns back to us, and I can tell he’s bothered.

“But that gas blanket in our atmosphere is getting thicker fast—much faster than when Gramps was a kid, even. Remember what we learned about the planet Venus? The atmosphere up there is so thick and things are so hot, there’s no way anything can live.”

“I do remember,” says Julie, her expression becoming serious too. “Our atmosphere keeps us warm, so everything doesn’t freeze, like on Mars. But if the atmosphere blanket around Earth gets too thick, we could all die of the heat, like on Venus.”

“How do you know that carbon dioxide in the atmosphere is increasing?” I ask Tom.

“I was using your laptop yesterday,” Tom says, glancing at Julie. “I typed carbon dioxide into Google and clicked on carbon dioxide emissions. The website said that people are causing a rapid increase in the amount of carbon dioxide in our atmosphere.”

“Let’s take a look at that website,” I suggest.

Tom opens the web browser, searches for carbon dioxide, and clicks on the carbon dioxide emissions link.

“Look.” He points to the screen. “It says that human activities—that’s us—are responsible for increases in carbon dioxide that have been happening since the Industrial Revolution.”

“What’s the Industrial Revolution?” Julie asks.

“A hundred and fifty years ago,” I explain, “our ancestors invented engines powered by oil and gas—fossil fuels. We use these engines for lots of really important things, like running trains and cars, and making electricity for lighting and heating our homes. Those engines changed our lives so much that we call it a revolution. So for the past hundred and fifty years we’ve been burning more and more fossil fuels.”

To Tom I say, “Okay, so burning coal and oil produces carbon dioxide that’s making the atmosphere thicker. Would you say that carbon dioxide is bad because it’s threatening life on Earth?”

My slight smile tells Tom that this question may be tricky, so he thinks hard before answering. “No,” he finally says tentatively, “we can’t say carbon dioxide itself is dangerous, because plants need it to grow, and the plants make oxygen from it that we all breathe to stay alive.”

Julie is looking at Tom, her eyes bright. “That’s right,” she agrees, “but you’re saying that too much carbon dioxide is the problem. We’re sending more carbon dioxide into the air than the plants and everything need!”

Tom nods in agreement. “The danger to Gaia is too much carbon dioxide.”

“What could happen if the atmosphere around the Earth keeps warming up?” I ask.

Water Woman sweeps a strand of hair back behind her ear. “The oceans will get warmer, and that might make it harder for the fish and krill and phytoplankton to live.”

“Good thinking, Julie. Tom?”

“The ice at the North and South Poles will melt. That’s already happening. I saw a program on TV about it.” He looks at me anxiously. “If the glaciers melt too much, cities along the ocean like Boston and New York will get flooded.”

“That’s true,” I say gently, “but we still have time to keep that from happening. What would happen on land if the air heats up a lot more?”

Julie looks nervous now, too. “It could be harder to grow things, like vegetables in our gardens and corn in the fields for the cows and chickens to eat.”

“And we’d probably see more wildfires,” Tom adds, “like they’ve been having out west lately.”

He stops then and goes back to my study, coming out with a piece of paper. “I’m going to make a list of dangers to life on Earth from too much carbon.”

Julie had been waiting silently, looking scared and even sniffling a little. Now she raises her head and says, “How will that help, Tom?”

“Well, it’s good to know what we’re up against,” I say, giving her a hug. “Let’s see what you guys can come up with.”

At the top of the paper, Tom writes

Threats to Gaia

and then the number 1, followed by

Too much carbon dioxide

“Where did you say that extra carbon dioxide was coming from?” I ask.

“Burning fossil fuels,” says Tom quickly, and Julie cries “Humans!” just as fast. I hand her a paper towel so she can blow her nose. Tom turns to his list and writes

2. People burning fossil fuels

“I can think of another threat to Gaia.” I point toward the grove of trees in front of the house. “Suppose we cut down those trees,” I suggest. “How would that affect the carbon cycle?”

Tom and Julie exchange looks.

“Well,” says Julie, without much confidence, “that would mean no trees to take carbon dioxide out of the air?”

Tom nods vigorously. “Trees soak up carbon dioxide and keep us cool that way. So the threat to Gaia is cutting down the forests and jungle, like they’ve been doing down in Brazil!” He turns to his list and scribbles

3. People cutting down the forests

Tom looks up from his list. “We’ve got to stop burning coal and the other fossil fuels, like oil and gas,” he says firmly.

“And stop cutting down trees!” Julie adds.

“Whoa, wait a minute!” I say. “How am I going to drive my car if I can’t use gas?”

“Gramps, you’re going to use electricity!” Tom answers impatiently.

“Julie, can cars run on electricity, like my electric tea kettle?”

She giggles. “Yes they can!” she says. “I saw an ad on TV. You just plug them in like a cell phone, and that charges their battery.”

“One big problem, though,” I say to Tom. “We have to use coal and oil to run the power plants that make the electricity.”

An Electric Car
This car runs on electricity instead of gasoline. It plugs into an electric outlet in your garage.

Tom frowns. “Yeah … we’ll have to work on that.” He flips over the paper, and on the other side writes

Friends of Gaia

“Maybe Gaia can help us out,” he says. “Let’s make a list of her friends. I’ll start with the sun.”

Below the title he puts the number 1, then writes

The sun

Right next to that he writes

for energy—but not too much

Julie gets up and stands beside Tom so she can see the list. “Put the oceans as number two!” she instructs.

Tom agrees, and writes

2. The oceans—because they soak up heat, keep things cool, and provide water to the atmosphere

“Tom, you mentioned the atmosphere,” I remind him. So he writes

3. The atmosphere—because it keeps us warm but not too warm, and carries water in clouds to the land

“How do the clouds over the ocean get to the land?” I ask.

“The wind! That’s part of the water cycle!” Julie squeals with excitement.

Tom writes

4. The wind—because it pushes clouds over the land

“The land is a friend, because it gives plants a place to grow,” Tom murmurs, almost to himself. He writes

5. The land—Earth’s crust—because it provides the soil for plants to grow in

“And the plants themselves,” he reminds us, “because they take carbon out of the air and turn it into the oxygen we need to breathe. They are also food we eat to stay alive and grow.”

6. The plants—they make oxygen by photosynthesis and give us food

Julie is thinking about food. “Sometimes we eat meat, like chicken or hamburgers, instead of plants like peas or corn. But chickens and cows eat grass and other plants—so I guess the plants get to us through their meat.”

“Way to go, Julie.” I give her a big smile. “Tom, let’s call animals friends of Gaia too, because they eat plants and provide us with meat.”

After number 7 he writes

7. The animals—eat the plants and give us meat for food

Julie examines the whole list. “That’s pretty good,” she murmurs. “Gaia has seven really important friends that work together—the sun, the wind, oceans, the atmosphere, the land we live on, the plants, and the animals.”

“I think the teamwork part is really important,” Tom says, learning back in his chair and stretching. “Your water cycle shows that really well, Julie. The oceans provide water. The atmosphere turns the water into clouds and carries it over the land. The land carries water to the plants, which make oxygen for us to breathe and food to eat. Everything works together to keep us alive!”

“That’s called a system—where different parts work together to make things better for everyone.” I stand up and stretch, too.

“You two don’t want to spend your whole last day in here, do you? I’m thinking it’s time to get outside and enjoy some of that sun and water.”

“Like our own bodies.” Julie bounces out of her chair and strikes a dancer’s pose, admiring herself. “My heart and my lungs and my blood and everything else all work together to keep me alive and happy. They’re like a system!”

“How about you two systems go put on your bathing suits, and we’ll head down to the beach?” I suggest.

“Tom, will you go sailing on the Sunfish with me? It’s our last chance,” Julie pleads. The Sunfish is a little boat the kids can sail. It’s tippy, but they wear life jackets and don’t mind getting wet.

“Sure,” Tom answers. “And I want to go fishing before we leave, too.”

A COUPLE OF HOURS LATER, we three are finishing our lunch on a blanket spread on the sand, watching a steady stream of boats parade through the Narrows. The Sunfish is pulled up on the beach, its sail flapping in the warm breeze. Tom and Julie sailed all the way around Sipson’s Island by themselves.

I pop open a container of cookies and pass it around. “I’m going to miss you guys a lot when you go home tomorrow.”

“Oh, but you can come see us in Boston any time you want!” Julie responds brightly. “Come to our soccer games, and you can stay overnight!”

“I’ll do that.” I give her a big smile.

“This morning at breakfast you seemed pretty worried about what might happen if the Earth keeps warming up. How are you feeling now?”

“Tom and I talked about that while we were sailing,” Julie answers, now looking thoughtful. “You were just saying that to make electricity, we need to burn lots of fossil fuels, and that’s what causes most of the warming. But Tom says there’s other ways to make power—like your windmill over there.”

She points up the path toward the wind machine rising above the trees behind the house, its blades spinning away. “That’s one way to make electricity without using coal or oil.”

Tom slides off the blanket and smooths the sand with his hands. “Yah, seeing your wind machine, I got to thinking maybe Gaia’s friends could help us find Goldilocks again. You know—make the temperature just right,” he explains. “So today we decided that Gaia has seven friends.” In the sand he writes a short version of his list, starting at the top with sun, then oceans, atmosphere, land, wind, plants, and animals.

“Let’s start with the sun.” Tom draws a sun in the sand. “People are putting solar panels on their roofs to make electricity, right, Gramps?”

“That’s true.” I nod. “I’m even thinking of putting some on my boathouse.”

“You mean to team up with your windmill?” Julie has drawn a simple windmill in the sand.

Tom circles wind on his list. “So we’ve got the sun and the wind to help keep the temperature of the Earth just right. What about the oceans? Can they help make electricity without putting more carbon into the atmosphere?”

“Water is used to make electricity,” I point out. “For a long time we’ve dammed up a lot of our rivers, so their water can be used to spin generators that produce electric power.”

Julie’s eyes brighten. “And the water in the rivers comes from the ocean!” she announces triumphantly. “Remember the water cycle? So the oceans are already helping make electricity!”

Tom is gazing out at the Narrows as the water floods in on the incoming tide. “All that water pouring into the bay and then out again—all day and all night, every day. I wonder if you could somehow use that energy to generate power?”

Next to the word ocean on his list he writes tides?

“What about the land, Gramps?” asks Julie. “You’re the crusty guy, right?”

I grin back at her. “Remember the mantle and the core, down underneath the crust of the Earth?” I remind her. “It’s pretty hot down there. Maybe we could capture some of that warmth and use it to heat our homes and factories.”

Tom looks impressed by that idea. He puts check marks beside sun, oceans, land, and wind on his list. “Hey, we’re doing pretty well,” he notes happily. “Let me think about the atmosphere. I’d say the atmosphere helps in lots of ways.”

“Like how, Gas Guy?” Julie loves to call Tom Gas Guy.

Tom thinks for a minute. “Well, I don’t know how it could actually make energy, but it allows the sun’s energy to come through and get to the solar panels—as long as the atmosphere doesn’t get too dense. And we’ve already talked about how it protects the Earth from getting too hot.”

Tom puts check a mark beside the atmosphere. “Two friends are left,” he declares, “the plants and the animals.”

“Plants are easy,” Julie answers, jumping to her feet and brushing sand off her knees. “They turn the sun’s energy into oxygen for us to breathe, and take carbon out of the atmosphere. That’s why we need to stop cutting trees down and plant more!” She twirls down the beach a short way and then back again, spraying us with sand.

Tom checks off plants, then puts a check mark by animals, too. “Animals are an important part of the poop cycle,” he says to no one in particular. “They fertilize the soil so plants can grow well.”

Looking at Tom’s list, I guess at what he’s thinking. “Are you saying that Gaia herself can actually show us how to keep Earth’s temperature just right, without burning carbon?”

Tom holds my gaze for a long moment. “I think so,” he finally says. “I think Gaia shows us where to look for energy without burning coal or gas or any of the fossil fuels.

“Sun, wind, and water. How they work together with the land and the atmosphere is awesome. We can use all three to make the energy we need—and the extra carbon can stay buried in the ground!”

Julie is already playing with Tom’s idea. “Sun and wind and water, I am Gaia’s daughter,” she chants. “Water, wind, and sun, they make me want to run!”

She dashes down the beach and sprints back. “Gramps!” she says breathlessly, “how do those solar panels on people’s houses turn the sun into electricity?”

“I don’t really know,” I admit. “If sun, wind, and water are the secret to keeping our world alive and healthy, then we need to learn about how all of them can make energy for us.”

Tom swipes across the sand, erasing his list. “Maybe we’ll learn some of those things in science class this year. I’m going to ask my teacher how solar panels work.”

“I’m Water Woman,” Julie reminds us, “so I want to learn how to use water to make electricity. Do you think my science teacher would let me do that?”

Tom isn’t sure. “Maybe you could do it as a special project,” he suggests. “When I was in sixth grade, we did those.”

“Perfect!” I say, packing up the remains of our picnic. “That leaves the wind for me. I’ll learn more about how my wind machine works and share that information with you two.”

“We can work as a team!” Julie crows. “Gramps, maybe you can come to our school and see what we’re learning!” She grabs a net and wades out into the shallow water to look for minnows.

Tom never comes down to the beach without his fishing rod. He picks it up, checks the lure at the end of the line, and heads for his favorite spot out on the point.

“Maybe I can catch one more bass before it’s time to leave.”

I WADE ANKLE DEEP into the water. To my right, Julie cruises back and forth, head down, looking for something to catch in her net. On my left, Tom flings his fishing lure out into the Narrows again and again. A horseshoe crab scuttles by, and minnows wiggle through the beach grass waving gently in the incoming tide.

Just as when I was very young, I can feel the Earth breathing.

I understand our living Earth much better than I did at the beginning of the summer. Tom and Julie have taught me a lot, and I’m excited about working with them to learn more about solar technology, wind machines, and water power.

Gaia already knows how to keep her temperature just right. We need to stop burning carbon so she can do her job. If we all work hard to make clean energy from the sun, wind, and water, our Earth will heal, and go on taking care of us. Fifty years from now, in a world powered by sun, wind, and water, Tom and Julie will be able to enjoy the bay and the beach just like we have this summer. That thought makes me very happy.