NASA Investigations of the Greenhouse Effect

Over the past 30 years, a number of satellite missions have been launched to obtain the data about Earth's radiation budget that are critical to understanding the greenhouse effect. Some of these missions are listed in the accompanying table.

Another very important aspect of greenhouse investigations has been the development of models. A number of climate models have been developed by NASA, and one of the most detailed is a General Circulation Model (GCM) developed by the Goddard Institute for Space Studies (GISS) in New York City. A GCM uses extremely high speed computers to solve the basic equations governing atmospheric motions and processes by numerical techniques. The GISS group, using its model, predicted that the annual global temperature would reach a new record high sometime during the first three years of the 1990's. Indeed, that record was reached in 1990. However, in June 1991, the Mount Pinatubo volcano erupted and sent 25 to 30 million tons of sulfur dioxide into the stratosphere. There, the sulfur dioxide reacted with water vapor to produce a long lasting haze of sulfuric acid droplets.

The GISS group then inserted the new information into the model, estimated how much sunlight the Pinatubo aerosol cloud would block, and predicted that the global temperature would drop about 0.3 degree C. Again, the predicted change actually occurred. Although these successful climate predictions are encouraging, most scientists agree that much remains to be done to improve climate models before we will be able to predict future climate in a credible manner.

An important need in the further development and verification of climate models is the acquisition, assembly, and analysis of reliable climate data. The highly accurate, self consistent, and long term data sets that will be acquired by the Earth Observing System (EOS), as part of NASA's Mission to Planet Earth with a series of satellite launches beginning in 1998, are designed to fulfill that need.

Greenhouse Gases - NASA

To predict climate change, one must model the climate. One test of the validity of predictions is the ability of the climate models to reproduce the climate as we see it today. Elements of the models such as the physics and chemistry of the processes that we know or think we know are essential to represent in the models. Therefore, the models have to embody the characteristics of the land and the oceans that serve as boundaries of the atmosphere represented in the models. Models also have to take into account the radiative characteristics of the gases that make up the atmosphere, including the key radiative gas, water vapor, that is so variable throughout the atmosphere.

Global records of surface temperature over the last 100 years show a rise in global temperatures (about 0.5 degrees C overall), but the rise is marked by periods when the temperature has dropped as well. If the models cannot explain these marked variations from the trend, then we cannot be completely certain that we can believe in their predictions of changes to come. For example, in the early 1970's, because temperatures had been decreasing for about 25 to 30 years, people began predicting the approach of an ice age! For the last 15 to 20 years, we have been seeing a fairly steady rise in temperatures, giving some assurance that we are now in a global warming phase.

The major gases in the atmosphere, nitrogen and oxygen, are transparent to both the radiation incoming from the sun and the radiation outgoing from the Earth, so they have little or no effect on the greenhouse warming. The gases that are not transparent are water vapor, ozone, carbon dioxide, methane, nitrous oxide, and the chlorofluorocarbons (CFCs). These are the greenhouse gases.

There has been about a 25% increase in carbon dioxide in the atmosphere from 270 or 280 parts per million 250 years ago, to approximately 350 parts per million today. The record of carbon dioxide in the atmosphere shows a variation as seasons change. This variation is more pronounced in the northern hemisphere, with its greater land area, than in the southern hemisphere because of interactions in the atmosphere caused by vegetation. In the growing season, during daylight vegetation takes in carbon dioxide; at night and in the senescent season, vegetation releases carbon dioxide. The effect is more pronounced in the northern hemisphere because most of the land on Earth is located there.

Global Climate Change

The prediction of climate change due to human activities began with a prediction made by the Swedish chemist, Svante Arrhenius, in 1896. Arrhenius took note of the industrial revolution then getting underway and realized that the amount of carbon dioxide being released into the atmosphere was increasing. Moreover, he believed carbon dioxide concentrations would continue to increase as the world's consumption of fossil fuels, particularly coal, increased ever more rapidly. His understanding of the role of carbon dioxide in heating Earth, even at that early date, led him to predict that if atmospheric carbon dioxide doubled, Earth would become several degrees warmer. However, little attention was paid to what must have been seen to be a rather far-out prediction that had no apparent consequence for people living at that time.

Arrhenius was referring to a potential modification of what we now call the greenhouse effect. A simplified explanation of this is as follows (see the diagram). Shortwave solar radiation can pass through the clear atmosphere relatively unimpeded, but longwave infrared radiation emitted by the warm surface of the Earth is absorbed partially and then re-emitted by a number of trace gases--particularly water vapor and carbon dioxide--in the cooler atmosphere above. Because, on average, the outgoing infrared radiation balances the incoming solar radiation, both the atmosphere and the surface will be warmer than they would be without the greenhouse gases. One should distinguish between the "natural" and a possible "enhanced" greenhouse effect. The natural greenhouse effect causes the mean temperature of the Earth's surface to be about 33 degrees C warmer than it would be if natural greenhouse gases were not present. This is fortunate for the natural greenhouse effect creates a climate in which life can thrive and man can live under relatively benign conditions. Otherwise, the Earth would be a very frigid and inhospitable place. On the other hand, an enhanced greenhouse effect refers to the possible raising of the mean temperature of the Earth's surface above that occurring due to the natural greenhouse effect because of an increase in the concentrations of greenhouse gases due to human activities. Such a global warming would probably bring other, sometimes deleterious, changes in climate; for example, changes in precipitation, storm patterns, and the level of the oceans. The word "enhanced" is usually omitted, but it should not be forgotten in discussions of the greenhouse effect.

Nearly 100 years after the Arrhenius prediction, we are now aware that carbon dioxide in the atmosphere is increasing, with the likelihood that it will double by the middle of the next century from the levels at the time of Arrhenius. Post-World War II industrialization has caused a dramatic jump in the amount of carbon dioxide in the atmosphere. As the prospect of considerable change in the atmosphere becomes more real and threatening, new computer models are being applied to the problem. These models take into account the natural processes that must be part of the whole picture to understand what could happen to Earth's climate as carbon dioxide increases. An important aspect of the newer models is their treatment of the "amplifier" or feedback effect, in which further changes in the atmosphere occur in response to the warming initiated by the change in carbon dioxide.

In addition to moisture and cloud processes, the newer models are beginning to take into account the role of vegetation, forests, grasslands, and crops in controlling the amount of carbon dioxide that actually will be in the atmosphere. Along with their role as "sinks" for carbon dioxide, the various types of vegetation in the biosphere have further effects on climate. Plants heat or cool the air around them (through the reflection and absorption of solar radiation and the evaporation process), remove momentum from surface winds, and take up and release moisture into the air (thus contributing to alterations in the hydrologic cycle). In turn, changes in climate will affect the patterns of vegetation growth. For instance, forest stands that require relatively cool conditions may not be able to adjust to the relatively rapid warming that is being predicted for the interiors of climates. With slow warming, scientists expect that the northern edges of North American forests would creep slowly forward to more-favorable conditions, while the southern edges would give way to grasslands that are better suited to the warmer conditions. With overly rapid warming rates, however, the loss at the southern edge would be more extreme, and the migration at the northern edges would not be able to make up for the loss at the southern edge.

Other feedback effects at work also must be considered. In normal conditions, plant leaves take in carbon dioxide from the air and release moisture to the air as part of the photosynthesis process. The release of moisture through evapotranspiration causes the air to cool. With increasing atmospheric carbon dioxide, one can expect to see a change in plant carbon exchange rates and water relations. This may result in reduced evaporation rates, thus amplifying the summer continental warming. Without plants, the ground and air would become warmer, exacerbating the problem.

Canadian Ice Shelf Loses 7 Square Mile Section

EDMONTON, Alberta. A chunk of ice spreading across seven square miles has broken off a Canadian ice shelf in the Arctic, scientists said Tuesday. Derek Mueller, a research at Trent University, was careful not to blame global warming, but said it the event was consistent with the theory that the current Arctic climate isn't rebuilding ice sheets.

"We're in a different climate now," he said. "It's not conducive to regrowing them. It's a one-way process."

Mueller said the sheet broke away last week from the Ward Hunt Ice Shelf off the north coast of Ellesmere Island in Canada's far north. He said a crack in the shelf was first spotted in 2002 and a survey this spring found a network of fissures.

The sheet is the biggest piece shed by one of Canada's six ice shelves since the Ayles shelf broke loose in 2005 from the coast of Ellesmere, about 500 miles from the North Pole. Formed by accumulating snow and freezing meltwater, ice shelves are large platforms of thick, ancient sea ice that float on the ocean's surface. Ellesmere Island was once entirely ringed by a single enormous ice shelf that broke up in the early 1900s.

At 170 square miles and 130-feet thick, the Ward Hunt shelf is the largest of those remnants. Mueller said it has been steadily declining since the 1930s. Gary Stern, co leader of an international research program on sea ice, said it's the same story all around the Arctic.

Speaking from the Coast Guard icebreaker Amundsen in Canada's north, Stern said He hadn't seen any ice in weeks. Plans to set up an ice camp last February had to be abandoned when usually dependable ice didn't form for the second year in a row, he said.

"Nobody on the ship is surprised anymore," Stern said. "We've been trying to get the word out for the longest time now that things are happening fast and they're going to continue to happen fast."

Is Global Warming Just HOAX?

These are just some thoughts on global warming denial and where we find ourselves at this point in time in relation to the environment.

Don't expect to find any solid data in this article to back my belief in the reality of catastrophic climate change, this is more of a heart piece I guess. I think there's so much data available now, it's a given. Just on this small site, there's hundreds of recent related news items summarized; collected just in the the first couple of months since I started Carbonify.com. What you see on this site doesn't even scratch the surface of the environmental disaster rapidly unfolding.

Ever since NASA's Goddard Institute for Space Studies made a correction to data that seemed to show 9 of the ten hottest years in U.S. history occurred since 1995 (turns out it was 3), the more vociferous of the "global warming deniers" have used this error to prove (they say) the whole idea of global warming induced climate change is a huge hoax. It smacks somewhat of desperation I feel.

I find it very difficult to believe that this one faux pas undermines the whole global warming credibility issue. I think it's a smokescreen so some folks don't feel pressured to make changes to lighten their impact on the environment.

If you've been used to living in a particular way and don't want that way to change, then denial of it possibly changing is a totally normal human reaction. It's a well known stage of grief. Wrap it up in a few cherry-picked facts and scientific gobbledegook and it even becomes believable.

But then again, the same can be said of the global warming believers I guess. I think the difference is the volume of data confirming the climate change reality - and not just words and numbers, but phenomenon we can see and feel.

Even if the U.N. came out tomorrow and said "ok, everyone, we got you good - global warming is a hoax" - I really wouldn't stop believing it unless many respected authors of various studies also admitted it's a hoax, if the Mauna Loa Observatory boffins said their atmospheric carbon dioxide data was a hoax and if my "spidey sense" said it was a hoax.

The "spidey sense" is an important element of all this to me.

In fact, a whole stack of organizations would need to come forward and say their data was a hoax before it would even put a dent in my convictions. I feel the planet dying, I feel the changes - have done since I was a child. I see the changes in plants and animals, I see the difference in the sunrises and sunsets. I feel the winds of major change; a whisper at first and now rapidly building into a storm. Global warming and climate change are only elements of it - we are witnessing a convergence of environmental crises - critical mass, toxic overload; whatever you like to call it.

When I was a fisherman and we were a long way out to sea, we knew to watch for a black line on the horizon. When it would appear, it was time to pull up our lines and skedaddle as it signified a storm was coming. If the storm should hit and we were still out there; there was nowhere to run and hide. I see the black line of global warming on our horizon now.

Animals are well adapted to detecting catastrophic change. We humans are not so sensitive, but we still have some of that instinct left over from our primitive past when we were more in touch with nature. Put the studies and debate aside for a moment. Reach inside yourself - what do you feel?

While my vision of the immediate future isn't rosey to some, it's not apocalyptic in the popular sense of the word by any means. The word "apocalypse" has its roots in Greek and means "the lifting of the veil". I do believe we're living in that time; religious beliefs aside. The apocalypse is not the end - it's the beginning. And like any storm, it will buffet us, create havoc, but behind it; the air will be clear and fresh.

Getting back to the deniers, many of them do raise a very valid point which certainly explains some of the recently more desperate nay-saying and screams of "hoax!". They are being marginalized. Some 'believers' are even going as far as saying their denial or skepticism borders on a crime against humanity.

The belief in climate change occurring has become so widespread, the deniers/skeptics feel threatened each time they express any opinion about a possible global warming hoax. Many are forming tight knit groups online to protect themselves, so they can continue to cling to their beliefs in a supportive environment. And that's perfectly natural too.

On an emotional level, I have this gut reaction that says that the global warming deniers are dangerous in that they interfere with alerting everyone to the dangers ahead and prevent the rapid, collective action necessary to minimize damage resulting from climate change. But on another level I know that's a very wrong way to be.

For starters, skepticism and denial are two very different states of being. A skeptic is someone who habitually or instinctively doubts or questions. Nothing wrong with that.

Debate is good. Various points of view being expressed is healthy. An opposing view seeking holes in a popular belief is wonderful. If the belief stands after all the holes have been pointed out and addressed, then belief becomes truth. The real truth.

I just don't think we've got a lot of time left to go through that process.

If anything, the various passionate diatribes and in some cases very intelligent arguments against the concept of global warming have done nothing but affirm my beliefs it's real, climate change is happening now.. and that it's going to have even far more reaching effects than I can comprehend at this point in time.

We need to let people have their opinion - allow them to express it and if they are doing so respectfully, treat it with respect. Listen to what they are saying; check out their sources. Far too often I see the global warming debate on forums and blogs denigrate into ad hominem attacks. This does nothing to help either side. It's simply wasting time.

Someone asked me a question along these lines recently; "if you believe in global warming so much, what's the point in living?" My response was basically, we all know we're going to die, so why do we continue to live? It's a basic imperative of living things to survive, but further to that, I see a chance at us minimizing the damage and perhaps a better world resulting from the changes about to occur.

Even if by some sort of miracle this global warming thing is just a big honest mistake; many of us have experienced an awakening. We've been alerted to the fact that we don't make rules on Planet Earth. We've taken steps to green our lives and generally be more respectful of the environment. Isn't that a good thing? Seems to me like it's the kick in the pants we've all needed.

Global Warming FAQ

What is global warming?

Global Warming describes is current trend in average temperatures around the world increasing as a result of human activity.
Using temperature measurements from historical records and current land and sea stations, in conjunction with satellite data; any doubt as to whether our planet is warming has been dispelled. Sea ice is retreating, glaciers are melting, species are migrating or disappearing and spring temperatures are arriving earlier each year.


What is the greenhouse effect?

The Greenhouse Effect is related to global warming in that it's the reason why excess heat from the surface of the Earth isn't dispersed into space. The glass on a greenhouse allows one type of radiation in, but reduces the amount another type can escape; causing the interior of the greenhouse to remain warm. This is what we are experiencing on our planet - gases such as carbon dioxide and methane act as the glass; allowing solar radiation in, but preventing heat from escaping.


Has global warming occurred in the past?

Yes, it has - while the earth has cooling and heating cycles, what we're currently seeing is a much more rapid change in temperature which is giving plants and animals far less time to adjust.


What human activities are linked to global warming?

Unfortunately, just about everything connected with modern society is a contributor. The cars we drive spew carbon dioxide into the atmosphere, as does coal powered electricity generation, production processes for many of our goods. Even the millions of livestock we keep for food play their part by producing methane.


Why are trees part of the answer to global warming?

During parts of a day, trees ingest carbon dioxide and produce oxygen. Mass deforestation has seriously compromized our planet's carbon dioxide recycling and conversion system.


Plant more trees and problem solved right?

Not quite. Nature maintains balances and humans are continually trying to override those rules. We haven't realized that this approach is endgame for the species. We need to soon. Trees are only part of the answer - we need to reduce our consumption and also commission more green energy resources such as solar, wind and geothermal electricity production. By buying green tags to offset your cars emissions and the emissions generated by your electricity supply, it helps investment into and supply of green energy.


How is carbon increasing global warming?

It isn't. People talk about carbon reduction, carbon emissions as a shortening of the term "carbon dioxide". We need to take carbon dioxide out of the air to allow some more heat from the planet to escape and convert it back into carbon; such as is stored in trees - hence the name of this site; carbonify.com.


How hot is it going to get?

The latest report from the Intergovernmental Panel on Climate Change predicts that our planet's average surface temperature will increase between 2.5° and 10.4°F (1.4°-5.8°C) between the 1990 average temperature and what it will be in 2100.


But it was cold last month! What gives?

There is a distinct difference between weather and climate. Weather is a set of meteorological conditions over a short span whereas climate is the average of those conditions over a longer period.


Hotter weather sounds good, what's the problem with climate change?

I don't like cold weather myself, but remember that Nature maintains a fine balance for a reason. Sudden changes in climate related to global warming will included :

• rapid melting of glaciers - loss of freshwater for humans, plants and animals that rely upon a steady flow
• extinction of plant and animals species that are very sensitive to temperature and unable to migrate
• tropical pests moving further south, bringing disease with them such as malaria
• low lying communities and countries being inundated by the see
• increased cyclones and hurricanes in some areas, severe drought in others.
• loss of habitat for animals such as the polar bear
• increased conflict among humans due to competition for resources

Can we avoid abrupt climate change?

Personally, I don't believe so. The amount of warming going on now will last for centuries and we have reached a tipping point. What we can do is to decrease the severity of what can occur if we act now - and right now. The longer we delay, the worse the affects will be.