Climate changes will arrive faster than previously assumed
The emission of greenhouse-gases increases according to the worst scenario of the UN Climate Panel, which will result in a 4,0 degree Celcius increase of global atmospharic temperature in 2100.
The UN Panel of Climate Change ( IPCC) has published its 4 th. report on climate change in spring 2007. The report tells, that the emission of greenhouse-gases not only is increasing but is accelerating, and that the concentration in the atmosphare is alarming high.
Global warming is today a fact according to observed increases in global temperatures of the atmosphare and the oceans, melting of snow and ice and rising of the sea level on a global scale.
The emission of greenhouse-gases is accelerating
The globale concentration of carbondioxide has increased from a pre- industriel level of 280 ppm to 379 ppm in 2005, and the concentration in 2005 was higher than the concentration in the last 650.000 years ( 180-300 ppm) as measured in icecores from deep drillings. In the last 10 years the velocity of increasing temperature accelerated from 1,4 ppm per year to 1,9 ppm per year. The yearly emission of carbondioxid from fossile fuels has globaly increased from 6,4 GTC in the 1990th to 7,2 GtC in 2002-2005.
The globale atmospharic concentration of the greenhouse-gas methan has increased from a preindustriel level of 715 ppb to 1774 ppb in 2005 and was much higher than the the concentration the last 650.000 years, which was 320-790 ppb.
The ice is melting and the sealevel is rising
In the periode 1961-2003 the sealevel rose by 1,8 mm/year, whereas the sealevel rose by 3,1 mm/year in the periode 1993-2003 as a consequence of thermic expansion and melting of snow and ice on land.
Satellite data since1978 show, that the extension of seaice of the Arctic Region was reduced by 2,7% per 10 years whith the greatest reduction of 7,4 % per 10 years in the summertime . In the summer 2007 the seaice in the Arctic Region was reduced by approx. 1 million squarekilometre compared to the worst year 2005. Scientists at the University of Colorado foresees that the seaice in the Arctic Region can be completely gone allready in 2030.
Since 1990 the area covered by permafrost on the northern hemisphare is reduced by 7% and by 15% in the spring.
Last time the polar Regions were remarkedly warmer than today 125.000 years ago, the reduction of polar ice made the oceans rise 4-6 m. Data from icecores indicate that the mean temperature of the poles was 3-5 degrees Celcius higher than today coarsed by the change of the orbit of the earth around the sun.
The climate becomes more extreme
In the periode 1900-2005 the rainfall has increased over North-and SouthAmerica,NorthEurope and the northern and eastern Asia. The frequency of intense rainfall has increased over most landareas in agreement with the increasing global warming and higher concentration of atmospharic water waper.
More draughts are observed in Sahara, the Mediterranian, Southern Africa and parts of the Southern Asia.
More intense - and longer - periods of draughts are observed in the tropics and subtropics since 1970.
The western winds have becom more intense on the globes midths latitudes, and an increase of strength of tropical cyclones has been observed.
In the last 50 years cold days, cold nights and frost have been less frequent, whereas hot days, hot nights and heathwaves have been more frequent.
Scenarios
IPCC shows results of climate modelling for different future scenarios:
Scenario Increase of
temp. Degr C sealevel cm
A1 Fast economic development and globilisation
A1FI Intensive use of fossil fuels 4,0 (2,4-6,4) 26-59
A1T Energy only from non-fossil fuels 2,4 (1,4-3,8) 20-45
A1B Use of different energy sources 2,8 ( 1,7-4,4) 21-48
A2 Protectionism. Slow growth and techn.development 3,4 (2,0-5,4) 23-51
B1 As A1, but fast transition to service and infosociety 1,8 ( 1,1-2.9) 18-38
B2 Locale solutions.Slow technology changes 2,4 (1,4-3,8) 20-43
Tabel 1. Definitions of scenarios and increases in temperature and sealevel in 2100
The worst scenario A1FI leads to a global increase of temperature of 4,0 degree Celcius, and the best scenario results in an increase of 1,8 degree Celcius.
The increase of temperature and sealevel in table 1 do not include the full effect of the changes of the icecaps and the uncertanty of the feedback mechanisms of the climate-carbon cycle according to the IPCC because of lacking published scientific litterature at the time of writing the report. The scenarios include the velocity of melting of ice on Greenland and Antarctis as observed 1993-2003 but not the increased and accelerating velocities as observed later.
More warming, ice-melting, draught and precipitation
The warming is expected to increase most over land and at the northern latitudes and less over the southern Ocean and parts of the Northatlantic Ocean.
The snowcover will decrease and the thawdepth will increase in regions with permafrost. The sea-ice will decrease in both Arctis and Antarctis in all scenarios. In some scenarios the summer-ice in Arctis will totaly disappear.
It is very likely, that extreme warm, heatwaves and heavy rain will continue to be more frequent. It is likely, that future cyclones will be more intense with higher windspeed and more heavy rain. More intense tropical storms wil move towars the poles inducing changes in winds, precipitation and temperature.
It is very likely, that the precipitation wil increase at high latitudes ( f.ex. Scandinavia), but will decrease at the subtropic area ( f.ex. Mediterrainen).
Emission of greenhousegases continue to increase
Numbers from EIA show that the emission of greenhousegases increased from 4,9 GtC in 1980 to 7,3 GtC in 2005. We are now following the worst scenario A1FI in the climatereport from IPCC. This sceanrio is a worldeconomy mainly based on fossil fuels and global economic growth. If we continue to follow this scenario, the earth will experience 4,0 degree C increase of temperatur in 2100.
The effect og greenhousegases is amplified
The smaller cover of white ice and snow wil reduce the reflection of sunradiation to the universe and increase the absorption of sunradiation by the earth, which will result in accelerating global warming.
New measurements have shown, that the effect of greenhousegases has been dampened the last decades by aerosols and sulphur particles more than previously assumed. At future reduction of the emission of sulphurparticles the temperature will increase compared to former climatemodelling.
Increasing temperatures risk releasing great amounts of methan from the tundra in Siberia, Canada and Alaska, which wil further amplify the greenhouse effect.
The ocean absorbs huge amounts of CO2, which dampens the effect of emission of greenhousegases. The ocean absorbs around 1/3 of the emission of CO2 from fossil fuels. Unfortunately new research indicates, that the Ocean at Antarctic aborbs less CO2, than previously assumed.
The sealevel can rise 12 - 65 meter
Since greenhousegases only very slowly is removed from the atmosphare, the emission from both the present and the past will contribute to global warming in more than thousand year ahead.
Global warming and rise of sealevel will continue for centuries, even if the emission of greenhousegases were stabilised today. If the emission is stabilised at the relative optimistic scenario A1B level, the thermal expansion of the oceans alone will result in a 30 - 80 cm increase of sealevel in 2300 - to which you have to add the increase of sealevel from melting of ice and gletchers.
The melting of the icecaps of Greenland and Western Antarctis will continue to add to the rise of sealevel beyond 2100. If the temperature rises more than 1,1 - 3,8 degreeC in more than thousand years the ice of Greenland and Western Antarctic will melt causing the sealevel to rise 7m respectively 5 m - totaly 12 m. If all ice is melting from Greenland and Anrarctic during thousands of years the sealevel will rise 65 m. However new research indicates, that a faster melting can occur according to a more easy mobility of the ice.
The ice melts faster than previously assumed
In the period 2001-2007 more precise measurements have been done of the mobility of the Hemlan gletcher in Greenland. By sattelite the mass of the gletcher is measured, and by GPS on the gletcher and the bedrock along the edge of the gletcher the front of the gletcher is measured. The measurements show that the melting has increased by a factor 4 from 2005-2007.
This indicates, that the ice of Greenland melts faster, than previously assumed. If the results from these measurements are extrapolated to whole Greenland, the melting will result in a 70 cm rise of the oceans during the next 25 years and approximately 3 m rise in 2100.
If the trend of emission of greenhousegases continue, the ice of the northern pole will melt. Allready today huge amount of ice has melted,but the melting will accelerate in the future.In approximately 30 years all ice will be gone at the Northern pole. The melting has an amplifying effect, because the ocean has a much greater absorption of sunradiation than the ice.
Draught, flooding and hunger in the developing countries
Draught and deserts will spread in Africa and parts of Asia, America and Europe.
Because of rising sealevel, more intensive storms and precipitaion, flooding will be more frequent and more severe in the heavy populated deltaes in South-and southeast Asia as Bangladesh. A big part of mankind lives in low lands along the coasts or along floods, which are fed by meltwater from ice and snow in the mountains.
We will experience increasing homelessness, hunger, thirst, poverty and illness especially in Africa and South Asia. Fight on resources and land as well as wars and massive amounts of refugees will be the next consequences of climate changes.
It is time for action.
