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Here you can ask questions related to emissions of CO2 and climate change. This column is answered by Dr. Hans Olav Hygen, Senior Scientist at the Norwegian Meteorological institute, and Max Hansson, Researcher at Centre for Climate and Safety, University of Karlstad, Sweden.
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CO2
Mr the expert, there have been a lot catastrophic previsions about the green house effects, and about the damage we do on the planet, but we'd like to know if a no return point has been reached, or if things are still reversible ?Peter Mac Alloway (13.03.2009 17:08)
I believe that it is possible to halt the anthropogenic part of the climatic change we experience. To do this is a massive effort all over the earth necessary. We have to strongly decrease the use of fossil fuels like oil and gas. The CO2 have to be decreased by 80 – 90 percent for the counties with the greater emissions, while some developing countries should be allowed a slight increase in emissions.
We can start this process today by making climate friendly choices for the future. A few exsapmles of climate friendly planning and actions is: City planners should make buss and train a more attractive alternative than car for the commuters, car buyers should go for low emission vehicle, new houses should be built to minimize the energy consumption.
These actoins has to start now, because the longer we wait the harder and more expensive is the required tasks.
When this is said is a response to the coming changes required. We are going to experience global warming for the next few decades. There are areas that will be stronger affected by flooding, droughts, etc. Due to the climate system beeing a huge system with slow response will the actions and plans set to work today have a stronger effect at the end of the century than the next few decades.
Hans Olav Hygen (19.03.2009 09:27) #
CO2 and sunlight
Was passiert genau mit den Sonnenstrahlen, nachdem sie von der Erde reflektiert wurden? Sofern ich weiss, verwandeln sie sich von kurzwelligen Stahlen zu langwelligen. Reagieren nur diese mit dem Co2 oder auch die kurzwelligen?Besten Dank
Giorgina (18.03.2009 20:36)
I'm not fluent in German so please forgive any misinterpretation of your question.
When the sunrays reach the earth’s surface they experience either reflection or absorption. The reflected rays will probably pass back out to space with no interaction with the atmosphere. The energy in the absorbed rays will be reemitted with a longer wavelength (usually infrared). All atoms and molecules absorb different wavelengths. CO2, and the other greenhouse gasses, has no absorption in the shorter wavelengths (e.g. visible light), but absorbs strongly in these longer wavelengths. Photons of infrared light typically pass about 10 meters in the atmosphere before they are absorbed. The energy will again be emitted as a photon, and travel a new distance before being absorbed. Reemitted from the molecule they can go in any direction, also back to the ground. This process will continue until the energy pass out of the atmosphere and into space. The key part in the greenhouse effect, and the increased greenhouse effect, is that the energy use more time from entering the earth’s atmosphere o leaving the atmosphere. This increased time gives more energy in the atmosphere, which we for example can measure as higher temperature.
Hans Olav Hygen (19.03.2009 09:08) #
Effect of clouds on climate
What are the effects of clouds and water gas on climate regulation and change ? Why are they not taken into account in the IPCC ?Begoña Oquiñena (17.03.2009 11:00)
Normally, the clouds in the air is the biggest greenhause gas, approximately 50-60 %. But, the clouds are not antropogenic. However, air pollution and dust particles mixed with the clouds, so-called "brown clouds" and white clouds" are causing a big dilemma. Recently UN released a report: http://www.unep.org/pdf/ABCSummaryFinal.pdf about this topic.
A worrying effect of particles in the brown clouds over Asia is their contribution to the ongoing melting of glaciers in the Himalayas. The melting depends on the soot (black particles) heating of the air over the region and probably also on the deposition of soot on glaciers. Glaciers are helping to smooth out the flow of water in the great rivers. If the glaciers would be significantly fewer and smaller, the risk of the rivers to dry out during the hot and dry pre-monsoon period in April-June will increase, which may have serious consequences for the population in the river valleys.
Reducing air pollution particles would also provide a great relief of the airborne particles harmful impact on human health (respiratory and cardiovascular diseases). A recent study by the UN Environment Program (Atmospheric brown clouds. Regional assessment report with focus on Asia) of the brown clouds environment shows that the clouds cause over 300,000 deaths per year in India and China. This estimate does not only soot but for all the airborne particles in the brown clouds.
The health risks underline the need for action was also against the emission of the other types of particles in the brown clouds, mainly sulfur and organic matter. However, this raises a fundamental and insoluble dilemma. These "white" particles have a very different impact on the climate. They do not absorb sunlight but reflects instead a part of the light back to space, and seems thereby cooled by the climate. A large part of greenhouse warming are masked today by the white particles cooling. Should we stop the emissions of these particles, which would be a big profit from health, we would run the risk of accelerated warming. Generally, contributing emissions from coal-fired power with both black soot particles and white sulfur particles, while small-scale wood and vehicles contribute the most with black soot particles.
Best wishes, Max
Max Hansson (18.03.2009 09:37) #
How many trees ?
Hello,A group of parents at our Zurich International School have calculated the CO2 emissions produced by cars driving to/from school (4 campuses) every day. They came up with 140t CO2 produced per school year. We would like to know how many trees we would have to plant to offset this amount of CO2 and what would be the best way to convey this message to the car drivers?
Any help from you would be greatly appreciated.
Many thanks,
Susi Khosla
Susi Khosla (18.03.2009 08:54)
Hello!
Normally, in UN:s calculations for carbon sequestration: 1 single tree, taking up approximately 1 ton during its life-time. I really the uptake differ a lot between tree species, but as guideline, 1 ton is used most of the times.
Best wishes, Max
Max Hansson (18.03.2009 09:19) #
We have a question
I want to ask you where i can find the formulars that we gave to the students?Audi Florentina, Bota Calin (13.03.2009 10:46)
Dear Audi Florentina,
You find an electronic version of the data sheet under 'What to do?' / 'Enter data sheet'. Teachers select the teacher-button and click 'Enter data' in the table to get to the electronic form, and pupils select the pupil entrance to go to the electronic data sheet using the pupils' login code.
Note that you must have the map coordinates set to reach the table showing your signed up classe under 'Enter data sheet' (green tick mark in front of the 'Map coordinates' link in the edit box when logged in). If there is a red cross in front of 'Map coordinates', you click 'Map coordinates' to set coordinates for your school.
Best regards,
Gaute Groenstoel (CO2nnect development team) (17.03.2009 16:55) #
Electric cars
Is it possible that electric cars replace classic cars ?Songo (13.03.2009 17:10)
To reduce our dependance on fossil fuels, we need to find alternative fuel sources for cars. One option for a more eco-friendly car is an electric car. In order to replace classic combustion engines with electric engines, an upgrade of the electric infrastructure is necessary. This is possible and the development of batteries with greater capacity tells me that electric cars is one of the solutions to reduce the emissions of Greenhouse gasses.
Remember, a car lasts typically 5 - 10 years, if we decide to change and rebuild the infrastructure, almost all cars could be replaced with electric cars in 10 years.
Hans Olav Hygen (16.03.2009 13:52) #
True or false
It's true that it takes on average about 20 milligrams of CO2 per second to visit a Web site ? I read this on a web page .Adriana Timofte (07.03.2009 21:43)
I haven't been able to verify this. I find that the manager of co2stats.org states this number, but there are other sources that give both higher and lower numbers.
Hans Olav Hygen (16.03.2009 08:51) #
do you think????
do you think about the shipping in currently make a lot of problem of weather?jureerat intarasareungkarn (06.03.2009 04:23)
The shipping around the world emits quite a lot of greenhouse gasses. To achieve a more sustainable future, these emisions will have to be limited.
Hans Olav Hygen (16.03.2009 08:37) #
Wind turbines.
Are wind turbines a good solution to produce energy in the future ?Songo (13.03.2009 17:08)
To avoid an uncontrollable climate change we need to be less dependant on fossil fuels (gas, oil and coal). To decrease this dependance, renewable sources, like wind turbines, is one of many possible and necessary paths. Applied in the right locations, use of wind turbines is a good alternative energy source.
Hans Olav Hygen (16.03.2009 08:05) #
Pupil log in code
I am a teacher and i want to know, how can i create Pupil log in code?Trentsiou Xrysoula (10.03.2009 11:09)
Dear Trentsiou Xrysoula,
If you don't have a teachers user account for your school, you first request a password via 'Sign up' / 'New user' and follow the instructions here to sign up your school or, if your school is already signed up, you request user access for your school. In the last step you sign up your class(es). When you sign up a class, a pupils code is generated for this class. Click 'What to do?' / 'Enter data sheet' / 'Teacher Log in with e-mail and password' and log in with your email address and password. Here you find a table listing your signed up classes. Click the key icon in the table to activate/show the pupil code. Give this code to your pupils and have them log in via 'What to do?' / 'Enter data sheet' / 'Pupil Log in with pupil login code' and they may enter and post their results. The code is valid for two weeks, and may be reactivated for another two weeks by clicking the green icon in the table.
Best regards,
Gaute Groenstoel (CO2nnect development team) (11.03.2009 13:30) #
Not logged in.