Clouds and climate modelsPerjantai 13.9.2024 klo 15.31 - Mikko Nikinmaa I have had heated discussions with climate change deniers, them saying that climate change is a hoax, since climate models do not take cloud effects properly into consideration. According to them, it is clear that clouds cause cooling, and if they were included, the models would not predict global warming. As evidence for their claim, they give the cooling caused by clouds formed by volcanic eruptions, and the decrease in temperature when the sunshiny day turns into cloudy one. Further, they maintain that whenever temperature increases, clouds will be formed causing cooling. Climate models include clouds, but because different cloud types, their stability and distribution affect climate in different ways, the uncertainties of the models are markedly increased by them. Further, contrary to what climate change deniers say, temperature increase is not associated with cloudiness and consecutive cooling. In fact, it appears that warming causes changes in clouds and cloudiness, which further increase temperature. The effects of clouds on climate models are difficult to estimate, because cloud altitude, the thickness of cloud, and the nature of the small particles (aerosols) gathering the moisture needed to form clouds all affect the temperature effects of clouds. For example, low-lying clouds can actually increase temperature, as they trap the heat, and prevent it from escaping; this is best seen in cloudy nights, which are much warmer than clear nights. In contrast, clouds at high altitudes have little heat-trapping capacity but, depending on the nature of particles in the cloud, effectively reflect sunlight thereby effectively cooling the atmosphere below. The particles in the clouds can be either reflective or absorptive, and cloud formation and dissolution give additional problems for climate models. Consecutively, clouds are presently the largest uncertainty of climate models. However, regardless of the cloud input, the models show that climate change is occurring. Furthermore, the models have improved considerably in the recent past, as both the cloud behaviour is understood better and the computing power has increased. The uncertainties of climate models caused by clouds can further decrease as a result of theoretical and experimental studies on them. |
Kommentoi kirjoitusta. Avainsanat: climate change, global warming, meteorology |
Climate Change and US Supreme CourtMaanantai 20.6.2022 klo 15.16 - Mikko Nikinmaa President Trump was able to nominate three Supreme Court judges during his presidency. This changed the Court to a significantly more conservative direction than earlier. This is now seen in the likelihood that the Roe vs. Wade decision from 1973 guaranteeing abortion right to women throughout USA will be overturned. But maybe even more terrible to the world is the West Virginia vs. EPA case, which the conservative Supreme Court judges likely decide in favour of West Virginia. That decision would mean that EPA would not be allowed to limit the carbon dioxide emissions of power plants. This would effectively mean that USA will not be able to combat climate change unless coal and oil industry wishes. In addition to this, there are several lower court cases, which would, e.g., limit the possibility of federal government to restrict carbon dioxide emissions of traffic or require that electricity production shifts from the use of fossil fuels to renewable energy. Altogether the conservative court cases may mean that the worst producer of greenhouse gases will not be able to carry out any meaningful actions in combatting climate change. Ironically, the conservative circles are working against any climate actions at the same time that the temperature in almost every part of USA has increased to highest level ever. And it is only mid-June. But, according to conservative circles, there is no connection between burning of fossil fuels and heat waves. Or is there? |
Kommentoi kirjoitusta. Avainsanat: global warming, fossil fuels, EPA, carbon dioxide emissions |
Strange WeatherPerjantai 12.1.2018 klo 10.53 - Mikko Nikinmaa Snow in Sahara, no snow in Southwestern Finland, bats dropping dead because of extreme heat in Sydney, drought followed by downpoor in California, record number of hurricanes in the USA and East Asia - the list could be continued almost to infinity... Whenever there is abnormal weather anywhere, the meteorologists are asked if this can be connected to climate change. Invariably they answer that this single phenomenon can occur even without climate change. That is true, and invariably they also state that weather is different from climate. Very cold weather can occur even if there is global warming. I can just imagine Trump tweeting "Hey, I even stopped global warming, when I said that it is not a threat. Look how cold it has been after that in North America." Unfortunately, the cold weather in USA and snow in Sahara actually fit very well in the climate change scenarios. All the predictions of climate change agree on three things: the temperatures near poles increase more that elsewhere, the predictability of weather decreases and the likelihood of unusual or extreme weather conditions increases. All these predictions have already taken place. They are, further, interconnected. Because the temperature difference between the poles and Equator decreases, the distribution of high and low pressure areas changes, and as a result the earlier predictable monsuuns or such like become unpredictable: it can snow in Sahara and rain in Finland. Also, the high pressures can persist and cause droughts with extensive wildfires occurring in consequence. At the same time extreme heat may occur. Temperatures close or even above +50 centigrade are difficult to tolerate. The unpredictability of weather is really the major problem. Human (and other) life has thrived as a result of predictable weather. One has always known that the rain comes more or less in the right time, it is cold when it is supposed to be, the extreme weather conditions never occur etc. That this is the case was actually shown by the bat deaths in Sydney. The bats have evolved in New South Wales for hundreds of thousands to millions of years. During that time they have adapted to the temperature conditions that can be expected. The recent +47 was above what their evolved tolerance could cope with, and they dropped dead from the trees. The predictability of weather is the prerequisite for food production. Agriculture requires rain at the right time, and dry period during harvesting. With climate change one year may bring you downpoor, another extreme heat and drought, and a third frost. All future generations are treated unjustly, if we don't actually demand our leaders all over the world to forget their slogans about their own nation first, and start enacting decisions which help keeping the world in reasonable state for future generations. |
Kommentoi kirjoitusta. Avainsanat: climate change, global warming |