The earth is getting hotter – or is it not? Has the Sun increased it´s shining during the last 150 years?
Our understanding of the the climate problem is not complete and will not be solved by focusing on CO2 alone. The calculation of carbon neutrality has to take into account the fact that the sun shines on the earth with a force of 1350 Wm2, whereas the effect due to burning fossil fuel is only 1-2 Wm2. As an example massive removal of forests in temperate zones will cool the earth, while deforestation in the tropics will increase the temperature.
Scientists haven’t been able to quantify accurately what the effect of CO2 on temperature is. Reduce CO2 or maybe it is just as effective to alter the reflective properties or color of the earth?
The albedo or reflective properties of the earth is an important concept in climatology and must be accounted for in the models used.
The albedo of an object is the extent to which it diffusely reflects light from light sources – in the case of the earth the Sun. It is a unitless measure between 0 and 1 indicative of a surface’s or body’s diffuse reflectivity. The word is derived from Latin albedo “whiteness”.
“Terrestrial albedo: Albedos of typical materials in the visible light range from up to 90% for fresh snow, to about 4% for charcoal, one of the darkest substances. Deeply shadowed cavities can achieve an effective albedo approaching the zero of a blackbody. When seen from a distance, the ocean surface has a low albedo, as do most forests, while desert areas have some of the highest albedos among landforms. Most land areas are in an albedo range of 0.1 to 0.4. The average albedo of the Earth is about 30%. This is far higher than for the ocean primarily because of the contribution of clouds. ” (Wikipedia)
Human activities have changed the albedo (e.g. forest clearance, farming) around the globe. Quantification of this effect on the global scale is difficult.
An example of the albedo effect is the snow-temperature feedback: a snow-covered area warms and the snow melts, the albedo decreases, more sunlight is absorbed, the temperature tends to increase. If snow forms, a cooling cycle happens. The intensity of the albedo effect depends on the amount of sunshine – it can be potentially very large in the tropics.
The Earth’s surface albedo is regularly estimated via Earth observation satellite sensors.
The Earth’s average surface temperature due to its albedo and the greenhouse effect is currently about 15°C. Based on theoretical models it has been estimated that for the frozen (more reflective) planet the average temperature is below -40°C. If all continents only were completely covered by glaciers the mean temperature would be about 0°C. The simulation for the more absorptive aquaplanet shows the average temperature close to 27°C.
There are CO2 critics: The journalist Christopher Monckton (among others) is critical of the theory of man-made causes for climate change and the stated scope of it – it is unlikely to prove catastrophic. He has criticized the Intergovernmental Panel on Climate Change (IPCC), their interpretation of the Medieval Warm Period, the “hockey stick” model. He supports the solar variation theory as a possible explanation of global warming. He states that Gore and the IPCC has systematically falsified and exaggerated the evidence for global warming.
Scientists are sceptical as well: Ferenc Miskolcz (among others) says that the Earth’s atmosphere dynamically keeps its greenhouse effect right at its critical value, regardless of our continuing CO2 emissions, regardless of any change in atmospheric CO2 concentration in the past ten thousand years. Miskolczi’s dynamic constraint keeps the greenhouse effect “climatically saturated”: emitting CO2 into the air cannot increase the normalized greenhouse factor g because any impact of human addition of CO2 is dynamically countered by about 1% decrease of the main greenhouse gas water vapor (moisture) in the atmosphere.
The aim must be to check, control or reduce total warming. Comprehensive models with a good combination of empirical and theoretical science must be established.