Would the deniers please explain why most of the world's glaciers, ice caps and winter freezing of the oceans has declined so dramatically in the last 50 years? I'd be happy to read a logical explanation other than the climate is getting warmer.
We are living in an interglacial period of an ice age. That means glaciers are melting, and have been doing so for the better part of 10,000 years.
Getting worked up over the last 150 years of warming since one of the worst cold snaps of the past 1000 years (the Little Ice Age) is ridiculous. Global temperatures in the early 1800s were some of the lowest since the dawn of human civilization. Of course it is warmer today. It still isn't nearly as warm today though as it was during the Roman or Medieval warm periods, or even as recently as the 1930s.
The funny thing is, what we really need to be worried about long-term is global cooling. Despite the warming over the last 150 years, the overall trend over the last 3,000 years is STEEPLY downward. Every 'warm period' over the last 2,000 years has been cooler than the last one. The one we are in right now is no different.
Here is a graph of ice core data showing temperatures over the last 10,000 years.
The warming trend we are currently in is that last bar off to the right. That graph should scare the piss out of people, because while global warming might be a slight-to-moderate problem over the next couple of hundred years from a species survival perspective, the longer-term cooling trend is a potential extinction level event. If bronze-age humans could survive the Minoan warm period, we can survive ours. But if we lapse back into a glacial period (which seems likely in the long-term), we are all fucked.
Your post doesn't really explain the uncharacteristic overall "heat snap" of the last 150 years. I'm not getting "worked up", I'm looking at figures and physical glaciation decline.
One of the most often cited arguments of those skeptical of global warming is that the Medieval Warm Period (800-1400 AD) was as warm as or warmer than today. Using this as proof to say that we cannot be causing current warming is a faulty notion based upon rhetoric rather than science. So what are the holes in this line of thinking?
Firstly, evidence suggests that the Medieval Warm Period may have been warmer than today in many parts of the globe such as in the North Atlantic. This warming thereby allowed Vikings to travel further north than had been previously possible because of reductions in sea ice and land ice in the Arctic. However, evidence also suggests that some places were very much cooler than today including the tropical pacific. All in all, when the warm places are averaged out with the cool places, it becomes clear that the overall warmth was likely similar to early to mid 20th century warming.
Since that early century warming, temperatures have risen well-beyond those achieved during the Medieval Warm Period across most of the globe. The National Academy of Sciences Report on Climate Reconstructions in 2006 found it plausible that current temperatures are hotter than during the Medieval Warm Period. Further evidence obtained since 2006 suggests that even in the Northern Hemisphere where the Medieval Warm Period was the most visible, temperatures are now beyond those experienced during Medieval times (Figure 1). This was also confirmed by a major paper from 78 scientists representing 60 scientific institutions around the world in 2013.
Secondly, the Medieval Warm Period has known causes which explain both the scale of the warmth and the pattern. It has now become clear to scientists that the Medieval Warm Period occurred during a time which had higher than average solar radiation and less volcanic activity (both resulting in warming). New evidence is also suggesting that changes in ocean circulation patterns played a very important role in bringing warmer seawater into the North Atlantic. This explains much of the extraordinary warmth in that region. These causes of warming contrast significantly with today's warming, which we know cannot be caused by the same mechanisms.
Overall, our conclusions are:
a) Globally temperatures are warmer than they have been during the last 2,000 years, and
b) the causes of Medieval warming are not the same as those causing late 20th century warming.