Dear Mr.Kashyapa, your reasoning is understood. Calendar has no role to mislead temperature, for a day, month or year, it is monitored in decade, century and thousand years like this and can not be easily sensed in a year or two. From this observation, it is clarified that ambient temperature is rising over the previous decades and centuries. Melting of glaciers on last few years at Antarctic regions and rise of sea level are clear indications of global warming. We may be staying in comfort air conditioned rooms and temperature rise may not be felt, but it is a fact that ambient temperature is on rise.

Thanks. I am not denying the existence of warming and the increasing rate of warming, as there is a lot of evidence from local observations, like what you point out. My doubt is on the method we calculate global warming.

Hi, I agree your point. but do we have other way to study? we need a reference where calendar has nothing to do, but we need a reference. 

Gentlemen

before asking or complaining that there should be ONE  reference:

There are 10,000s of publications on climate change and for a compilation everyone interested can read the report(s) of the United Nations/ World Meteorological Organisation, known as IPCC reports.

It is on the web to be down-loaded for free. You can start with the Technical Summary

 http://www.ipcc.ch/report/ar5/wg1/

There you will see that climate change is in the first place seen in the rise of the GLOBAL average temperature. Regional changes are (also) connected to regional variations like the "El Nino"

 https://www.ncdc.noaa.gov/teleconnections/enso/indicators/soi/

I just found out that even a pioneer in global temperature calculations (Hanson J. et al, 2010, "Global surface temperature change", Review of Geophysics, 48) has acknowledged the error arising out of the use of the calendar year to calculate temperature anomalies. In that paper, they were worried that if El Niño or a volcanic eruption were to occur as the calendar year changes, their effects will not be reflected clearly in the yearly temperature change. Hence they suggest using a 12-month running mean of the temperature change instead of yearly values. Even that does not take the error out in the case of seasonal changes associated with Climate Change as we pointed out. Anderson et al (2012, "Phenotypic plasticity and adaptive evolution contribute to advancing flowering phenology in response to climate change", 11 July 2012, Proccedings of the Royal Society B Biological sciences, UK.), with long term monitoring of the appearance of a local flower, provide clear evidence for such seasonal changes.

A useful tip for those of you trying to understand how extreme climatic events (instead of just average temp and rainfall values) have changed over the years. Donat et al (2013) have presented a detailed analysis on global effects using temperature and precipitation related indices.

Article Updated analyses of temperature and precipitation extreme in...

Still climate is the average state of the atmosphere and the impacts arising from this for a long period of time (at least 30 years). As it was mentioned already above, such long observation period balances climate variations that occurs parallel to the climate and represents itself in our weather, say in a given year. We then compile the weather data for a place in a period, the average temperature, rainfall etc. in a given year. Of course it might make a difference, if we let the year start with January or with June, as we then consider different 12 months periods, which might be different as a result of climate variability / weather but the overall climate data over 30 years is little affected by this, if at all.

Planet Earth is about 4.5 billion years old and in this long time there had been periods that were much, much warmer than it is today (e.g. during the time dinosaurs lived on our planet) and also periods that were far colder (ice ages). In other words: it would be strange when the climate would be the same indefinately. This never has been the case. There were also periods when CO2 concnetration was much higher than today. Indeed there was a time when no O2 was in the atmosphere...

Climate change is something that bothers us, because we are effected, because we are there to be bothered. It does not effect Planet Earth in any meaningful way as the planet will be there even if Human aren't anymore (although also Planet Earth won't be eternal). Among many other challenges the scientific mainstream believes that the generation of special gases through the burning of fossil fuels is the driving force for climate change. A few, however, see human contribution little in global warming and some even talk of global cooling.

In RG there have been many contributions that put global warming and global cooling as two different processes. What is different is the outcome of very complex processes. The outcome is either warming or cooling, and to make it even more complex both can happen - in different places.... or at differnt times (a specific place can have warmer summers and colder winters as a resukt of change of the climate....,). How much of this change is contributed by human activies we can discuss and do research about, but it would be strange if only humans have contributed to these changes, or if they would be entirely caused by natural processes - both is very unlikely the case.

Sometimes people think that IPCC does investigate into global warming, but indeed it looks into climate change. The expression global warming is out since many years as it is acknowldeged that it is much more than around temperature change. Global cooling, if it exists is also climate change.

In Germany we can have temperatures in winter of minus 20 degrees Celsius. That is winter and we call this winter weather. Some years winters are mild, other years very harsh, long and very cold. Weather and climate are different things, and the weather is never the same. It changes and also if the sun energy received on January 1 at a particular place would be the same every year (which is not the case as the sender (sun) sends not always the same) it still would result in different weather as the energy received is only one from many, many factors that makes the weather.

In the discussion often people speak of a food crisis because of global warming. I doubt that this is the only possible interpretation. Today we produce considerable more food per capita than a few decades ago. When people are starving then it is usual because of the impacts of wars, civil wars, ethnic tensions, or just because of poverty, but not necessarily because of climate change, at least not so directly as often assumed. Here in the Pacific Island countries the talk of climate change and its impact on food security has been rather dominant, despite this part of the world does not know widespread undernutrition and when we look at malnutrition than we discover that the biggest concern is obesity, and when we would anlyze the causes then we would not find climate change, but MacDonalds and other fast food outlets.

I think that a cooling effect (if it exists) due to reduced sun activity moderates anthropogenic warming impacts, the same other natural impacts on the climate would such as volcanic eruptions etc. We should realise that something as complex as climate has many contributing factors that lead to change.

To assume that everything is caused by humans or everything by natural causes is far too simplistic. For that reason it is rather difficult to make any precise predictions of the future. So both (processes that contribute to warming and such contributing to cooling) not only can happen, but they do, and they always did. What now is sold as new ideas and change to previous scientific knowledge is actually nothing really new other than that one aspect from an extremely complex process is taken out and displayed as the whole truth.