When Ice Ruled the Earth

Continuing the journey in to the mysterious Earth

For children and curious minds of all ages

Yogendra Deva

 

The photographs from Aaba's Char Dham pilgrimage had found an unexpected admirer.

It was Mihir.

He had quietly copied the photographs onto his tablet and spent the next few evenings exploring them at his own pace. After reading Aaba's travelogues, the photographs seemed to tell a story of their own.

One afternoon, he walked into Aaba's room carrying the tablet.

"Aaba, I think something is wrong."

Aaba looked up from the book he was reading.

"With the tablet?"

"No."

"With the photographs?"

"I think so."

Aaba smiled.

"Photographs usually don't make mistakes."

"They do if people misunderstand them."

Now Aaba was interested.

He removed his spectacles, wiped them carefully with his handkerchief, and put them back on.

"Let's see this troublesome photograph."

Mihir placed the tablet on the table.

It showed the road to Gangotri winding beside the Bhagirathi River. Snow-clad peaks stood quietly in the background. Along the river lay enormous grey boulders, scattered as though a giant had emptied a bag of marbles. Only these marbles were the size of small cars, and a few looked almost as large as little houses.

Mihir enlarged the photograph until one of the boulders filled the screen.

He tapped it gently.

"This fellow."

Aaba studied it with the seriousness of a doctor examining an old patient.

"A handsome specimen."

Mihir looked unconvinced.

"It isn't handsome."

"It is," said Aaba. "If you look at it as a geologist."

"Geologists need stronger spectacles."

Aaba laughed.

"That observation has been made before."

Mihir pointed towards the Bhagirathi River flowing beside the boulders.

"My problem is not the rock."

"It is the river."

Aaba leaned closer.

"What about it?"

"Could it really have brought this boulder here?"

Aaba remained silent.

"The river isn't nearly big enough."

"I quite agree," said Aaba.

Mihir grinned.

"I knew it!"

He folded his arms, looking rather pleased with himself.

"So, if the river didn't bring it, what did?"

Aaba closed his book and walked to the window.

Outside, the gulmohar tree swayed gently in the afternoon breeze. A pair of mainas were arguing noisily over something that probably seemed very important to them.

He turned back.

"That, Mihir," he said quietly, "is one of the finest questions a curious mind can ask."

Mihir's eyes brightened.

"You mean there is an answer?"

"There is."

"It wasn't carried by the Bhagirathi."

"No?"

"No."

"It was carried by another river."

Mihir looked puzzled.

"I don't see another river."

"You wouldn't."

"It disappeared thousands of years ago."

Mihir stared at him.

"A disappearing river?"

Aaba nodded.

"Yes."

He paused just long enough to let Mihir's imagination run ahead.

"It was a river made of ice."

Mihir stared at Aaba.

"A river made of ice?"

"Yes."

"But ice doesn't flow."

"It does," said Aaba. "Just far too slowly for us to notice."

He pointed to the clock on the wall.

"Can you see the hour hand moving?"

Mihir looked carefully.

"No."

"Yet, by the time we've finished talking, it will have moved a little. A glacier behaves much the same way. It moves so slowly that you never notice it, but year after year it quietly travels downhill."

Mihir was still doubtful.

"But it's solid."

"It is. Under the enormous weight of hundreds of metres of ice, it slowly bends and creeps forward."

"It really is a river."

"A very slow one."

"How slow?"

"A snail," said Aaba, "would probably complain about the traffic."

Mihir laughed.

"And that slow fellow carried those giant boulders?"

"It certainly did."

Aaba tapped the photograph.

"But this is only the beginning of the story."

"There is more?"

"Much more."

He smiled.

"To understand these boulders, we must travel back about twenty thousand years—to a time when ice ruled a large part of the Earth."

Aaba picked up the tablet again.

"Close your eyes for a moment."

Mihir obeyed.

"Imagine we are standing exactly where this photograph was taken."

"Near Gangotri?"

"Yes."

"What can you see?"

"The temple."

"It hasn't been built yet."

"The road?"

"There isn't one."

"The river?"

"It exists... but not as you know it."

Mihir opened one eye.

"You've changed everything."

Aaba laughed.

"We've travelled twenty thousand years into the past. The world looked very different then."

Mihir shut his eye again.

"What do I see now?"

"A gigantic river of ice filling the entire valley."

"The whole valley?"

"From one mountainside to the other."

"And the Bhagirathi?"

"Hidden beneath hundreds of metres of ice."

Mihir's eyes flew open.

"Hundreds of metres!"

"Yes. The glacier was so thick that only the highest peaks looked above it, rather like islands rising from a frozen sea."

Mihir stared at the photograph again.

"No road."

"No temple."

"No pilgrims."

"Only ice."

"And silence," said Aaba softly. "A silence broken only by the occasional crack of the glacier as it slowly crept downhill."

Mihir shivered.

"It sounds lonely."

"It was."

He looked once more at the giant boulders in the photograph.

"And when the glacier finally melted..."

"...it quietly left those giant rocks behind."

"Exactly where we find them today."

Mihir smiled.

"So those handsome fellows..."

Aaba chuckled.

"...are old travellers."

"Very old travellers."

"Older than pyramids?"

"Much older."

"Older than dinosaurs?"

Aaba laughed.

"Not quite. Even handsome fellows have their limits."

Mihir looked thoughtful.

"Aaba?"

"Yes?"

"Was only Gangotri covered with ice?"

Aaba smiled.

"No, my dear fellow. Gangotri was only a tiny corner of an astonishing world."

"What do you mean?"

"Imagine flying high above the Earth."

"Higher than an aeroplane?"

"Much higher."

"Higher than Everest?"

"Far higher."

"What would I see?"

"You would wonder where half the continents had disappeared."

"Disappeared?"

"They were hidden beneath enormous sheets of ice."

Mihir's eyes widened.

"Entire countries?"

"Many of them."

"What about India?"

"Only the highest Himalaya wore its icy blanket. But North America, northern Europe and large parts of Asia were covered by ice that was sometimes more than three kilometres thick."

"Three kilometres!"

"Enough to bury Delhi's tallest buildings several times over."

Mihir whistled softly.

"Who switched on such a giant freezer?"

Aaba laughed.

"Nobody knows the whole story. Scientists believe the last Ice Age was mainly driven by orbital changes in Earth’s motion around the Sun, which reduced summer sunlight in the Northern Hemisphere and let snow and ice build-up year after year. Once ice sheets grew, they amplified the cooling by reflecting more sunlight."

"It didn't happen in one winter?"

"No. The Earth has much more patience than we do."

Mihir nodded.

"I've noticed that."

"For tens of thousands of years, winter kept winning."

"And then?"

"Very slowly, the Earth began to warm again."

"The ice melted?"

"Most of it."

"And the glaciers?"

"Many became smaller and retreated into the high mountains, just as we see them today."

Mihir looked once again at the Gangotri photograph.

"Then these boulders..."

"...are letters," said Aaba.

"Letters?"

"Yes. Messages left behind by the glaciers."

Mihir smiled.

"And geologists know how to read them."

Aaba returned the smile.

"They spend their whole lives learning the language."

Mihir walked to the window beside Aaba.

The afternoon sun was shining brightly.

"It doesn't look much like an Ice Age."

Aaba smiled.

"Fortunately."

"Could another Ice Age come again?"

"It almost certainly will."

Mihir looked alarmed.

"You mean... all this could become ice again?"

"Not tomorrow. Not next year. Probably not for thousands of years."

Mihir let out a sigh of relief.

"I was wondering where we would keep the car."

Aaba laughed.

"I suspect snow chains would become more popular than umbrellas."

Mihir looked out thoughtfully.

"The Earth keeps changing, doesn't it?"

"It never stops."

"It builds mountains."

"It does."

"It breaks them."

"It does."

"It buries forests."

"Yes."

"It freezes continents."

"Yes."

"And then melts them again."

Aaba nodded.

"That is why geologists never say 'This is how the Earth has always been.'"

"What do they say?"

"They ask, 'What happened here before?'"

Mihir picked up the tablet once more.

The giant boulder no longer looked ordinary.

"It has travelled farther than I ever have."

"It has."

"And it remembers an Ice Age."

"It does."

Mihir smiled.

"I shall never look at a rock the same way again."

Aaba put an arm around his shoulder.

"That's the day a geologist is born."

Mihir looked once more at the giant boulder.

"I think..."

"Yes?"

"It looks handsome."

Aaba beamed.

"I knew you were improving."