Attribution of recent climate change

• Attribution of recent climate change is the effort to scientifically ascertain mechanisms responsible for recent global warming and related climate changes on Earth. The effort has focused on changes observed during the period of instrumental temperature record, particularly in the last 50 years. This is the period when human activity has grown fastest and observations of the atmosphere above the surface have become available. According to the Intergovernmental Panel on Climate Change (IPCC), it is “extremely likely” that human influence was the dominant cause of global warming between 1951 and 2010. Likely human contribution is 93%–123% of the observed 1951–2010 temperature change. They are like increasing atmoshperic concentrations of green house gasses , for a warming effect, global changes to land surface, such as deforestation, for a warming effect, increasing atmospheric concentrations of aerosols, mainly for a cooling effect.
• Probability density function (PDF) of fraction of surface temperature trends since 1950 attributable to human activity. In addition to human activities, some natural mechanisms can also cause climatic change including for example, climate oscillations, changes in solar activity, and volcanic activity.
• A physical understanding of the climate system: greenhouse gas concentrations have increased and their warming properties are well-established. Historical estimates of past climate changes suggest that the recent changes in global surface temperature are unusual.Computer-based climate models are unable to replicate the observed warming unless human greenhouse gas emissions are included.
• Natural forces alone (such as solar and volcanic activity) cannot explain the observed warming.Factors affecting Earth’s climate can be broken down into feedback and forcings. A forcing is something that is imposed externally on the include natural phenomena such as volcanic eruptions and variations in the sun’s output. Human activities can also impose forcings, for example, through changing the composition of the atmosphere.
• Radiative forece is a measure of how various factors alter the energy balance of the Earth’s atmosphere. A positive radiative forcing will tend to increase the energy of the Earth-atmosphere system, leading to a warming of the system. Between the start of the Industrial Revolution in 1750, and the year 2005, the increase in the atmospheric concentration of  Carbon oxide led to a positive radiative forcing, averaged over the Earth’s surface area, of about 1.66 watts per square metre (abbreviated W m⁻²). An example of internal variability is the El Niño–Southern Oscillation.

(Images/video taken from google/IE)

2020 Nobel Prize in physics black holes

• A black hole is an object so compact that nothing can escape its gravitational pull, not even light. They are formed when stars die and start collapsing under their own weight. Deep inside the black hole resides an infinitely hot and dense object, a so-called, singularity.  Black holes are perhaps the most mysterious objects in nature. They warp space and time in extreme ways and contain a mathematical impossibility, a singularity – an infinitely hot and dense object within.

• Robert Penrose is a theoretical physicist who works on black holes. Dying stars form black holes. Sir Roger Penrose won half the prize for his seminal work in 1965 which proved, using a series of mathematical arguments, that under very general conditions, collapsing matter would trigger the formation of a black hole. 

• Black holes play yo-yo with stars – The remaining half of the prize was shared between astronomers Reinhard Genzel and Andrea Ghez, who each lead a team that discovered the presence of a supermassive black hole, 4 million times more massive than the Sun, at the center of our Milky Way galaxy. Genzel is an astrophysicist at the Max Planck Institute for Extraterrestrial Physics, Germany and the University of California, Berkeley. Ghez is an astronomer at the University of California, Los Angeles.

(Images/video taken from google/IE)

Trippy ‘reverse waterfalls’ seen flowing backwards in

• Rivers in Arizona run black with steaming sludge and red “blood snow” stains the Antarctic Peninsula, you may not be surprised to learn that several waterfalls in southeast Australia have been flowing backwards during middle of August 2020.
• Water pours over the cliff tops of the New South Wales coast, the stream curves back up and sprays backwards onto land. Partway through the footage, the gravity-defying mist also creates a rainbow that seems to say. Obviously, there is a simple meteorological explanation for this reverse-waterfall action: It’s just a trick of the wind.
• The strong coastal winds were more than enough to temporarily divert the course of the falls and, unfortunately, they also wreaked havoc on surrounding communities. Hundreds of residents of New South Wales were urged to evacuate their homes for three days during the peak of the storm. The coastline’s wild weather caused rivers to flood and left thousands of homes without power. The rain has finally subsided, thankfully, and the evacuation order has been lifted

(Images/video taken frfom google/IE)