Global Warming is, itself, the product of many factors, and its relevance to anything else depends on its magnitude. Emissions of minor greenhouse gases are a factor, but only one factor (and probably not the most important) among several.

The sun is commonly mentioned, but the fact of the matter is that the climate system does not need any external forcing to fluctuate on the scale that has been observed. The ocean, by constantly but irregularly exchanging heat between deeper and shallower regions is always out of equilibrium with the surface, thus serving as a large source or sink of energy for the atmosphere. In the literature, this variability goes by names like El Niño, the Pacific Decadal Oscillation, and the Atlantic Multi-decadal Oscillation – all indicative of time scales on the order being considered. 

Here is a recent pale reconstruction for the past 2000 years. Most presentations focus on the last 100 years or so (and show the modest warming that we are talking about), but in the context of the past 2000 years, the last 100 years do not appear exceptional.

Effects

Predicting the consequences of global warming is one of the most difficult tasks faced by climate researchers. This is due to the fact that natural processes that cause rain, snowfall, hailstorms, and rise in sea levels are reliant on many diverse factors. Moreover, it is very hard to predict the size of emissions of greenhouse gases in the future years as this is determined majorly through technological advancements and political decisions. Global warming produces many negative effects some of which are described here. Firstly, extra water vapour which is present in the atmosphere falls again as rain which leads to floods in various regions of the world. When the weather turns warmer, the evaporation process from both land and sea rises. This leads to drought in the regions where the increased evaporation process is not compensated by increased precipitation.

 In some areas of the world, this will result in crop failure and famine, particularly in areas where the temperatures are already high. The extra water vapour content in the atmosphere will fall again as extra rain hence causing a flood. Towns and villages which are dependent on the melting water from snowy mountains may suffer drought and scarcity of water supply. It is because the glaciers all over the world are shrinking at a very rapid rate and the melting of ice appears to be faster than previously projected. According to Intergovernmental Panel on Climate Change (IPCC), about one-sixth of the total population of the world lives in the regions which shall be effected by a decrease in melting water. The warmer climate will likely cause more heatwaves, more violent rainfall, and also amplification in the severity of hailstorms and thunderstorms. The rising of sea levels is the most deadly effect of global warming, the rise in temperature is causing the ice and glaciers to melt rapidly. This will lead to rising water levels in oceans, rivers, and lakes that can pilot devastation in the form of floods. As evident from Fig. 5, temperature anomalies are projected to increase in the coming years. Before the 20th century, the situation was well under control but at the beginning of the current century, the situation started to worsen. This was all due to an increase in global warming majorly due to the fact that new industries and powerhouses started operation and emitted harmful gases which cause the planet to heat up. This data is based on the research carried out by different climate and environmental research agencies.