IPCC warns of irreversible impact of global climate change

Tags: Popular Science and Technology

The Intergovernmental Panel on Climate Change (IPCC) has warned of a grim future for earth if global warming continues and the global temperatures continue to increase beyond 1.5% . 

• The latest warnings have come in the second part of IPCC’s Sixth Assessment Report which talks about climate change impacts, risks and vulnerabilities, and adaptation options. The first part of the report was released in August last year.

• The Assessment Reports, the first of which had come out in 1990, are the most comprehensive evaluations of the state of the earth’s climate. Later reports were released in 1995,2001,2007 and 2015.

The report highlights the increasing impacts that are expected as the rise in global temperatures, currently around 1.1C, heads to 1.5Cabove the 1850s level.

Highlights of the report 

•  South Asia is the most vulnerable to severe climate change impacts due to its inequality and poverty .

• The Ganga, Indus, Amu Darya river basins in Asia will face severe water scarcity by 2050.It will adversely affect agriculture and drinking water scarcity in the region .

• Ahmedabad city faces a risk of urban heat island effect . It means that the average temperature in the city will be higher than the surrounding areas.

• Mumbai is at a high risk of rising sea level and consequent flooding

• If the temperature increases by 1-4  degree centigrade then rice production in the world can fall by 10-30% and maize production can fall by 25-70%.

• If temperatures rise to between 1.7 and 1.8C above the 1850s level, then the report states that half the human population could be exposed to periods of life-threatening climatic conditions arising from heat and humidity.

Rising Sea Level 

According to the IPCC report, global sea levels will likely rise 44-76 cm this century if governments meet their current emission-cutting pledges. With faster emission cuts, the increase could be limited to 28-55 cm.

But with higher emissions, and if ice sheets collapse more quickly than expected, sea levels could rise as much as 2 m this century and 5 m by 2150.

Wet Bulb Temperature

• Lucknow and Patna ,Bhubaneswar, Chennai, Mumbai, Indore, and Ahmedabad , are among the cities predicted to reach wet-bulb temperature of 35°C if emissions continue to rise.

•  Assam, Meghalaya, Tripura, West Bengal, Bihar, Jharkhand, Odisha, Chhattisgarh, Uttar Pradesh, Haryana and Punjab will be the most severely affected, but if emissions keep rising, all States will have regions that experience wet-bulb temperature of 30°C or more by the end of the century.

IPCC 

The Intergovernmental Panel on Climate Change was set up by the World Meteorological Organisation and the United Nation Environment Programme in 1988.

 Aim of IPCC

It was set up to prepare a comprehensive review and recommendations with respect to

•  the state of knowledge of the science of climate change;
• social and economic impact of climate change, 
•  potential response strategies and elements for inclusion in a possible future international convention on climate.

Its Headquarters : Geneva, Switzerland 

Current Chairman : Hoesung Lee 

It shared Nobel Peace Prize with the  former American  Vice-President Al Gore in 2007

Concept Clearing 

What is Wet Bulb Temperature 

Human body regulates our body  temperature depending upon the external environment of heat and humidity.  If the temperature is high then our body tries to lower down our body temperature by sweating.  The more we sweat the faster the cooling.  However if humidity (water vapour in air ) is high then the ability of our body to cool also reduces . That’s why dry heat feels more tolerable than extreme humidity.

Wet-bulb temperature accounts for both heat and humidity, and reflects what that combination means for the human body’s ability to cool down.

The term wet bulb comes from a way the measurement can be taken, by wrapping a piece of wet cloth around the end of a thermometer to see how much evaporation can decrease the temperature.

35 degree centigrade is considered to be the maximum limit for a wet bulb temperature.

If the wet bulb temperature reaches 35 degree centigrade then a normal healthy human being cannot lose its body heat by sweating and will suffer heat stroke leading to death if they remain outdoors for a considerable period of time.

With the  continuous rise in earth temperature the risk of wet bulb temperature phenomena is expected to become common.