Clearer than ever: global warming is for real

Scientists are now 95 per cent certain that global warming is human-induced

By Arnab Pratim Dutta
Last Updated: Tuesday 25 August 2015

The fact that gradual warming of the earth is caused by humans was reinforced by the latest assessment report from the Intergovernmental Panel on Climate Change (IPCC). The first of the three-part report, collectively called Assessment Report 5 (AR5), was released on Friday in Stockholm. It says that involvement of humans is clear in the alteration of the planet's climate patterns. It says that the changes in the climate patterns are unprecedented.

“Observations of changes in the climate system are based on multiple lines of independent evidence. Our assessment of the science finds that the atmosphere and ocean have warmed, the amount of snow and ice has diminished, the global mean sea level has risen and the concentrations of greenhouse gases have increased,” said Qin Dahe, co-chair of IPCC Working Group I.

“Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased,” notes the report. Human influence has been detected in warming of the atmosphere and the ocean, in changes in the global water cycle, in reductions in snow and ice, in global mean sea level rise, and in changes in some climate extremes. This evidence for human influence has grown since AR4. It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century, the report says.
Changes predicted 

Business as usual will lead to more havoc and the planet will require substantial reduction in green house gas emissions to keep temperature rising beyond 1.5°C by the turn of the next century, says the report. “Global surface temperature change for the end of the 21st century is projected to be likely to exceed 1.5°C relative to 1850 to 1900 in all but the lowest scenario considered, and likely to exceed 2°C for the two high scenarios,” said co-chair Thomas Stocker. Heat-waves are likely to become more frequent and will last longer while the wet regions will receive more rainfall and dry regions will have greater droughts, the co-chair said.

There is a good chance that monsoons which is of key importance to India will see anomalies. The report says that it is likely that the area encompassed by monsoon systems will increase over the 21st century. “While monsoon winds are likely to weaken, monsoon precipitation is likely to intensify due to the increase in atmospheric moisture. Monsoon onset dates are likely to become earlier or not to change much. Monsoon retreat dates will likely be delayed, resulting in lengthening of the monsoon season in many regions,” the report states.

The IPCC report says global surface temperature change at the end of the 21st century is likely to exceed 1.5°C relative to 1850 to 1900 (courtesy:

The oceans are also likely to get warmer especially the upper layer of the ocean ranging from 0 to 700 metres in depth. “Ocean warming dominates the increase in energy stored in the climate system, accounting for more than 90 per cent of the energy accumulated between 1971 and 2010 (high confidence). It is virtually certain that the upper ocean (0−700 m) warmed from 1971 to 2010,” the report notes.

“As the ocean warms, and glaciers and ice sheets reduce, global mean sea level will continue to rise, but at a faster rate than we have experienced over the past 40 years,” said Dahe.

The report finds with high confidence that ocean warming dominates the increase in energy stored in the climate system, accounting for more than 90 per cent of the energy accumulated between 1971 and 2010.

The report has used four scenarios of future greenhouse gas (GHG) concentrations and aerosols, spanning a wide range of possible futures. This report assesses the global warming in the 20th and the 21st century. It notes that effects of climate change will persist for a many centuries even if the world puts a complete halt to CO2 emissions.

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  • Namaste, IPCC is now


    IPCC is now presented its AR5 report. In this connection I would like to bring to your kind information some points ÔÇô three questions and answers. I in fact posted this in The New York Times/Science/Environment/Dot Earth, discussion section on the topic ÔÇ£The vital long view in tracking diminishing Arctic Sea iceÔÇØ.

    1. "According to the Commonwealth Scientific and Industrial Research Organization, sea levels on average have been 20 centimeters higher than they were in the 1880s. Water levels are rising at 3.2 millimeters per year, which is double the 20th century trend."

    In the past on several forums I made the following observations but nobody come forward to respond my question: (1) San Francisco Airport is in the Ocean waters. Was there any rise in sea water level at this point? -- so far no change [I visited several times]; (2) In Italy along the coast, traditional and historical wells showed no change in sea level; (3) It is generally argued that the sea level raise submerged the Sundarbans at the mouth of Ganga River in the Bay of Bengal and villages along Bramhaputra River in Bangladesh -- all this is inaccurate statements. Here the silt deposition from these two mighty rivers causing the submergence of Mangroves and hutments; (4) Also, destruction of Coastline for commercial activities and destruction of Mangroves allowed sea water entering into nearby villages and thus people are attributing it to sea level rise; (5) In several parts, sea sand is lifted for other uses and thus causing the sea water entering in to nearby areas; and (6) Boston area was filled [artificially built] and with the storm surges it looks something happened.

    Also, sea temperatures are higher in some places and some other places they are cool associated with general circulation patterns existing generally in those zones. These infect the sea level temporarily -- natural variations. Unless we analyze region-wise by taking into account on ground variations in the light of general circulation, natural variations & physical impacts, all model estimates are speculative in nature and create sensation that pickup media.

    2. "ocean acidification [due to higher CO2 levels] and warming are causing species like jellyfish to overrun other species in the sea and bleaching and decreasing growth of coral reefs"

    In the oceans, temperature change and along with carbon dioxide change is a historical fact. They clearly indicate a clear cut cyclic variations -- I put this in my book "Climate Change: Myths & Realities" published in 2008. As this is not new the life in the ocean automatically adopt to these variations. There is a need to look into other man induced pollution factors in to ocean waters angle to understand their impact on coral reefs as well other species in the ocean. Our research, therefore, must direct to understand the cause and effect mechanism. With the preconceived ideas we go nowhere. This is exactly what is happening now. This is bad science -- though many a times such studies are published in reputed journals, as editorial boards work "you scratch my back and I scratch your back".

    3. "The physical principles behind climate change are simple, well known since the 1800s, and won't wait for this fake debate to end."

    This point I did not understand, here climate change means a de facto global warming or all issues pertaining to changes in climate. As per global warming there are no clear cut physical principles. We can see in the literature every other day a new issue comes up. Now, even IPCC also changed and telling urban-heat-island affect also contributing to global warming by about 10% -- initially they did not accounted this --. There are several other issues like natural variation component, solar components, ecological changes components [that influence local and regional climate], physical impacts on ecological sensitive zones like ice, etc. It is not clear on the link between carbon dioxide and temperature. It is a statistical link. It varies with the accumulation of data series period and it does not explain the physical relationship.

    The main component that at present influencing climate and extremes is the natural variations -- systematic & irregular variations -- and ecological changes such as changes in land use and land cover -- effect local and regional climate and thus change the natural variations to that extent. At Antarctica the sea ice melt in the last six years is above the mean while it is below the mean in Arctic area.

    Finally, what is the accuracy of data used in AR5 of IPCC both in terms of space and time, more particularly carbon dioxide and ocean temperatures as well surface temperatures? How much is manipulated as widely reported in media. Let us emphasize the need to look at issues related to climate change at local and regional with indigenous studies rather than copied from IPCC AR-5 report or Western MNCs propaganda materials.

    Dr. S. Jeevananda Reddy

    Posted by: Anonymous | 7 years ago | Reply
  • Here are few more points to

    Here are few more points to ponder upon:


    Three things to consider:

    1) Why don't they just show the annual temperature graph? They always thought it most appropriate in the past.

    2) Why do they begin this graph in 1850? Anthropogenic Climate Change, according to their report, could not have started before *19* 50 (a hundred years later). So why isn't the chart, and all the ballyhooed temperature increase, started in 1950?

    3) If AGW didn't start (couldn't start, actually, as we hadn't yet added the CO2 to the atmosphere), what caused the temperature rise starting in 1890? Whatever that cause is, what made that cause stop and suddenly change to CO2 -caused in 1950?

    Appreciate your answers.

    Models present a monotonic increase as the models are built with some preconceived notions -- that means what you are able to think only goes in to the model.

    Nature in fact acts differently based on several unknown and known factors. So, the real pattern goes on changing with the time.

    However, this is affected by scientists manipulation of data and changes in land use and land cover as weather is highly sensitive to such variations. Also, we are experiencing changes due to man's physical actions and manipulation of terrain. These changes are alarmingly increasing with population growth and changing technologies to meet their lifestyles and needs.

    In global models such factors taken in to account rarely. Also natural disasters do change the terrain conditions. And above all, the natural variations are not the same over different parts of the globe.
    Instead of talking on a generalized term "global warming", it is more appropriate to use the term "regional climate changes". This is more useful in regional planning.

    Global temperature data is manipulated, global carbon dioxide data is manipulated. Meteorological data collection is changing with the time over land and in/on oceans with network and instrumentation changes. Satellite data is highly manipulated!!!

    In 70s & 80s, before encroachment of global warming in to climate studies, before starting analyzing rainfall data by clubbing the rainfall of different rain gauge stations, we used to homogenize the rain gauge stations in terms of rainfall patterns. This helped to understand the climate of different parts in a region. This helped better interpretation of the results so analyzed in terms of agriculture or water management. It appears this is lacking in IPCC studies and counter positive and negative trends giving false notions or predictions.

    Other important issue is, IPCC talks of probability. Probabilities relevance with data but not number of people accepted it. This is bad science.

    Dr. S. Jeevananda Reddy

    Posted by: Anonymous | 7 years ago | Reply
  • Excellent article. Yes.

    Excellent article. Yes. Global warming is real and Human's intervention is also clear.
    Dr.A.Jagadeesh Nellore(AP),India

    Posted by: Anonymous | 7 years ago | Reply