Stories tagged national geographic

Sep
20
2011

There’s been some buzz about the relationship between clouds and climate recently, prompting Andrew Revkin of the New York Times’ Dot Earth blog to get his panties in a twist about the “…over-interpretation of a couple of [scientific] papers…”

What gives? I wanted to know too, so I’ve done a bit – ok, a lot – of research and this is what I can tell you: The heart of the discussion is not whether there is a cloud-climate connection (that’s clear), but rather over what that relationship behaves like. There are at least three possible theories, but before we get to those, let’s review some important background concepts.

Gimme the Basics First

Cloud Formation

First, scientists think of air as units of volume called air masses. Each air mass is identified by its temperature and moisture content. Clouds are basically wet air masses that form when rising air masses expand and cool, causing the moisture in the air to condense. You can see the process in action yourself just by exhaling outside on a cool morning. The Center for Multiscale Modeling of Atmospheric Processes has a webpage to answer your other questions about clouds.

Earth’s Energy Budget
Earth's energy budget: Incoming solar energy is either absorbed (orange) or reflected (yellow).  Outgoing energy is radiated (red).  The arrows show the direction and magnitude of movement where thick arrows signify bigger movements.
Earth's energy budget: Incoming solar energy is either absorbed (orange) or reflected (yellow). Outgoing energy is radiated (red). The arrows show the direction and magnitude of movement where thick arrows signify bigger movements.Courtesy NASA

Energy from the Sun is essential for life on Earth. Let’s pretend the Earth has an “energy budget” where solar energy is like money, absorption is like a deposit, reflection is like a transfer, and radiation is like a withdrawal. It’s not a perfect analogy, but it’ll work for starters: Most of the incoming solar energy (money) is absorbed by (deposited into) the ocean and earth surface, but some is absorbed or reflected (transferred) by the atmosphere and clouds. Most of the outgoing energy is radiated (withdrawn) to space from the atmosphere and clouds. The figure to the right illustrates this process.

The Greenhouse Effect

Thanks to the greenhouse effect, our planet is warm enough to live on. The greenhouse effect occurs within the earth’s energy budget when some of the heat radiating (withdrawing… remember our budget analogy from above?) from the ocean and earth surface is reflected (transferred) back to Earth by greenhouse gases in the atmosphere. Greenhouse gases include carbon dioxide, methane, and water vapor. This National Geographic interactive website entertains the concept.

Climate Change

Climate change is occurring largely because humans are adding more greenhouse gases to the atmosphere. More greenhouse gases in the atmosphere means more heat reflected back to earth and warmer temperatures. Warmer temperatures might sound pretty good to your right now (especially if you live in Minnesota and could see your breath this morning as you walked to school or work), but it’s not. Why? Check out NASA’s really great website on the effects of climate change.

Alright, already. What’s the climate-cloud relationship?

From what I can tell, there are three possible theories about the climate-cloud relationship:

  • Clouds actively drive climate change. This is a linear process where clouds reflect too much heat back to Earth, which increases the average global temperature and causes climate change.
  • Clouds passively blunt climate change. This is a cyclical process where more climate change includes increasing average global temperature, which increases average global evaporation, which creates more clouds. More clouds absorb more heat, keeping the average global temperature from rising even faster and lessening climate change. This slows down (note: it does not stop) the rate of climate change.
  • Clouds passively amplify climate change. This is a cyclical process where more climate change includes increasing the average global temperature, which increases average global evaporation, which creates more clouds. More clouds reflect more heat back to Earth, which raises the average global temperatures and worsens climate change. This speeds up the rate of climate change.
  • So which is it? Probably NOT Theory #1. Maybe Theory #2… or maybe it’s Theory #3? Scientists aren’t quite sure yet, so neither am I, but the evidence is stacking against Theory #1 leaving two possible options. The next big question seems to be surrounding the size of the effects of Theory #2 and Theory #3.

    Using what you just read about cloud formation, the earth’s energy budget, greenhouse gases, and climate change (Woah. You just learned a lot!), what do you think? What’s the climate-cloud relationship?

    If you want, you can read more about what scientists are saying about the climate-cloud relationship here:

Last week, National Geographic published some stinkin' fantastic photos of trees cocooned in spider webs. Apparently high flood waters in Pakistan caused the web-spinning critters to scurry to high, dry land -- namely these trees.

Here are some fun points from the article:

"The giant spider webs in Sindh, Pakistan, sometimes stretched from tree to tree..."

"...scientists determined that dozens of spider species were spinning the communal webs."

"The huge webs ultimately killed many of the trees they covered, perhaps by reducing the amount of sunlight reaching their leaves. But for a while, the webs also seemed to help trap more mosquitoes in the region, thereby reducing the risk of malaria..."

"While unusual, trees cocooned in spider webs are not unprecedented. Scientists have reported similar webs in other parts of the world, the tropics in particular."

The annual GeoBee geography challenge is taking place this week. Sort of like a spelling bee, the contest tests students' geography knowledge. How do you think you would do? Test yourself on National Geographic's GeoBee Challenge website.

UPDATE 5-21-09: Check out the video below to see the final questions leading up to the crowning of this year's champion.

Do you enjoy learning about elephants? National Geographic has a fun read about The Elephants of Samburu. Warning: This feature is 12 pages long.

So what did you do over the weekend? I guess we all missed these wild times going on in Botswana, Africa. Check out this video of an elephant pool party. I wonder if the Republican National Convention will get this crazy here in St. Paul in September?

Dec
04
2007

Welcome to Buzz blog

Hundreds of new visitors came to our Buzz blog last week because their google search for "dinosaur mummy" pointed to my post titled Fossilized dinosaur mummy gets x-rayed. The internet buzz this week is about another dinosaur mummy. A hadrosaur, or duck-billed dinosaur, was discovered in 1999 by then-teenage paleontologist Tyler Lyson on his family's North Dakota property. It is not really a mummy (dried tissue), but a fossilized mummy (composed of rock).

"This specimen exceeds the jackpot," said excavation leader Phillip Manning, a paleontologist at Britain's University of Manchester."

Why fossil dinosaur mummies are rare

"First the dinosaur body had to escape predators, scavengers, and degradation by weather and water. Then a chemical process must have mineralized the tissue before bacteria ate it. And finally, the remains had to survive millions of years undamaged." National Geographic

Dinosaur mummy prompts new modeling

CT scans of the hadrosaur's fossilized muscle mass and computer modeling leads scientists to speculate that Dakota (the name given to this dinosaur mummy) could run 28 mph. This makes sense because hadrosaurs were being chased by the Tyrannosaurus rex which topped out at about 20 mph. Scientists warn that errors in computer modeling can be 50 per cent, though.

Could there be DNA preserved in Dakota?

Most scientists refused to comment until their finds are published and undergo the scrutiny of peer review. Peggy Ostrom, who studies how organisms are related to each other, commented only in general terms.

"It's rare to find an articulated skeleton and even more so to find one with fossilized soft tissue,"
"If such finds show extraordinary preservation, they tempt us to wonder about the possibility of finding [unfossilized] biomolecules that might be remnants of the ancient organism."

Kristi Curry Rogers from our Science Museum of Minnesota has commented on "the preservation of identifiable fossil proteins" in this Buzz post.

Want to learn more about mummy dinosaurs?

Video: Dinosaur Mummy Found
National Geographic News article: dinosaur mummy, Dakota
National Geographic: dinosaur main page

"Operation Migration" leads whooping cranes from Wisconson to Florida every October. Watch how on this National Geographic video. You can track their progress here.