Projection of Climate Departure: Assessing Climate Change

Scientists at University of Hawai have projected the timing of climate departure from the present variabilities. First of all, let me explain to you what this means. The climate is changing at a very slow pace , thus the changes in ecological and social parameters due to climate change are extremely less when considered for a small time scale. However, when viewed at a large time scale, they appear to have changed a lot as does the climate. So, the scientists have tried to project/predict the time period till which the climate will change to such extremes which has not occurred in last 145 years. 

They presented an index for the time when the projected mean climate of a given location moves to a state continuously outside the bounds of historical variability under alternative greenhouse gas emissions scenarios. The historical variabilities they have considered in this study are from 1860 to 2005. So, the temperature conditions being assessed for a city when it hits the "climate departure" are such that the average temperature of the city's coolest year from then on is projected to be warmer than the average temperature of its hottest year between 1860 and 2005. 

This index has a global mean of 2069 (±18 years s.d.) for near-surface air temperature under an emissions stabilization scenario and 2047 (±14 years s.d.) under a ‘business-as-usual’ scenario. This means that if we stabilize the emissions, the climate departure for near-surface air temperature will occur in 2069, that is, 56 years from now (solid blue line in fig c); and in the case of continuing emissions at our present rate (which will increase with time) with no additional boundations on emissions, the climate departure will occur in 2047, that is, 34 years from now (solid red line in fig c).

a, b, Projected year when annual (a) or monthly (b) air temperature means move to a state continuously outside annual or monthly historical bounds, respectively.c, Absolute change in mean annual air temperature. (Results in a–c are based on RCP85.) d, Cumulative frequency of 100-km grid cells according to the projected timing of climate departure from recent variability for air temperature under two emissions scenarios (vertical lines indicate the median year). e, Scatter plot relating the grid cells from the map of absolute change (c) to the same grid cells from the map of projected timing of climate departure (a).
Source: http://www.nature.com/nature/journal/v502/n7470/full/nature12540.html

They also found out that the unprecedented climates will occur earliest in the tropics and among low-income countries, highlighting the vulnerability of global biodiversity and the limited governmental capacity to respond to the impacts of climate change. The study states, "The fact that the earliest climate departures occur in low-income countries further highlights an obvious disparity between those who benefit economically from the processes leading to climate change and those who will have to pay for most of the environmental and social costs."

They also emphasised on the emission control measures required by the developed countries as, "This suggests that any progress to decrease the rate of ongoing climate change will require a bigger commitment from developed countries to decrease their emissions but will also require more extensive funding of social and conservation programmes in developing countries to minimize the impacts of climate change."

Their study is of significance in terms of the urgency of mitigating greenhouse gas emissions if widespread changes in global biodiversity and human societies are to be prevented. 

Following is the image representing the year of climate departure of various cities for both emissions control measures scenario and business-as-usual scenario.

Climate Departure with carbon dioxide mitigation
Source: The Washington Post

Climate Departure without carbon dioxide mitigation
Source: The Washington Post

One of our Indian cities, Mumbai, as predicted will have a climate departure in 2034 (approx 20 years from now) without carbon dioxide emissions mitigation and 2051 with mitigation.

The study can be accessed here: http://www.nature.com/nature/journal/v502/n7470/full/nature12540.html

Journal: http://www.nature.com/nature/index.html

Read more ...

Science Fact - 19

The body of Jeremy Bentham is stuffed with hay and preserved at the University of London since 1832. 

Jeremy Bentham (15 February 1748 – 6 June 1832) was a British philosopher, jurist, social reformer and the founder of modern utilitarianism. 

Bentham died on 6 June 1832 the age of 84 at his residence in Queen Square Place in Westminster, London. He had continued to write up to a month before his death, and had made careful preparations for the dissection of his body after death and its preservation as an auto-icon. As early as 1769, when Bentham was just twenty-one years old, he made a will leaving his body for dissection to a family friend, the physician and chemist George Fordyce. A paper written in 1830, instructing Thomas Southwood Smith to create the auto-icon, was attached to his last will, dated 30 May 1832.

Afterward, the skeleton and head were preserved and stored in a wooden cabinet called the "Auto-icon", with the skeleton padded out with hay and dressed in Bentham's clothes. Originally kept by his disciple Thomas Southwood Smith, it was acquired by University College London in 1850. It is normally kept on public display at the end of the South Cloisters in the main building of the college; however, for the 100th and 150th anniversaries of the college, and in 2013, it was brought to the meeting of the College Council, where it was listed as "present but not voting".

Read more ...

Solar Flip

Our Sun is about to flip! Yeah that's right but it doesn't mean that we need to flip out! The magnetic poles of the Sun are about to flip, that is, the North pole will become the South pole and vice versa. According to scientists at the Wilcox Solar Observatory at Stanford University , the Sun could be barely two to three months away from this magnetic field reversal. 

What does it mean?

The solar dynamo is the physical process that generates the Sun's magnetic field. The Sun is permeated by an overall dipole magnetic field, as are many other celestial bodies such as the Earth. It means that just like our earth has a magnetic field and thus, North and South poles, in a similar way Sun also has a giant magnet inside it with North and South poles. So we can think of the sun as a large N-S magnet, like our Earth, but with smaller variously oriented and continually evolving mini-magnets distributed over its photosphere (visible surface) and throughout its corona (extended atmosphere).

How does it flip?

Solar magnetic reversals occur close to solar maximum, when the number of sunspots is near its peak, though it is often a gradual process, taking up to 18 months. Indeed, as is the case now, one pole often lags the other by some months. Currently, the sun has two positive magnetic poles! "The sun's north pole has already changed sign, while the south pole is racing to catch up," says Scherrer. "Soon, however, both poles will be reversed, and the second half of Solar Max will be underway."

The reversal will probably be complete within the next one or two months. It happens at the peak of each solar cycle as the sun's inner magnetic dynamo re-organizes itself. The coming reversal will mark the midpoint of Solar Cycle 24. Half of 'Solar Max' will be behind us, with half yet to come.

The Sun's large scale magnetic field flips over on a regular basis, roughly every 11 years. Actually, Earth's flips too, very irregularly. The last time was 780,000 years ago. (PhysOrg)

Will it affect us?

Dibyendu Nandi, an astrophysicist at Kolkata's Indian Institute of Science Education and Research said, "The weather in space is expected to be most hazardous in the next few months as the flip begins to take place. The chances of solar magnetic storms occurring are also high. These storms carry a vast amount of charged particles and magnetic fields through interplanetary space and can pose a threat to satellite operations , telecommunications , air traffic on polar routes and power grids in countries at high latitudes". 

Scientists are watching the event closely to fully understand the changes that take place. It's also of special interest because the current solar cycle — the 24th since 1755, when sunspot activity began to be recorded — is one of the weakest in 100 years. A strong solar magnetic field also acts as a shield against cosmic rays coming from outer space. "Due to the current weak cycle, we have been recording high cosmic ray influx since 2009," said B N Dwivedi of IIT-BHU.

What we need to know is whether this flip leads to change in earth's magnetic field or not! Because that might lead to a lot of changes in our geographical  and climatic features.

Isha Khanna

Read more ...