Combined land/sea surface temperatures since the late 1800s

Land and sea surface temperatures since the late 1800s. Data, from 1880 on, is broken down into high, low, and southern latitudes:

Source: NASA GISS data set

Extent of multi-year ice in the Arctic

Extent of thick, multi-year ice in the Arctic relative to 1-year old ice, dating back to 1984:

Source on the image.

Ocean heat content since WWII

Oceans are known to have taken up much of the excess heat generated by increased CO2 over the past century. But how much? Here is data taken from seven different sources, beginning in the early 1940s:

Northern Hemisphere snow cover since 1920

Northern hemisphere snow cover during the max March to April timeframe since 1920:

Sources listed on the graph.

Sea level changes since 1870

Two graphs of sea level change, one from 1870-2000, the other from 1993 to 2011:

Sources listed on the graphs.

Sea level since 1870

Sea level trends since 1870, from 6 different research groups:

Source: NASA

Cosmic rays and climate change

Researchers at CERN have recently demonstrated that cosmic rays may have an effect on ionizing some compounds in the Earth's atmosphere. Their data show changes on compounds that are too small to act as seeds for cloud formation - some have theorized that cosmic rays could spur cloud formation, cooling the atmosphere. If so, then during periods of low sun activity (low cosmic rays), the Earth would heat up due to decreased cloud cover. While research from CERN indicates that cosmic rays have the potential to be a climate forcer (similar to the sun's luminosity and sunspots), the data do not support the theory that cosmic rays are the primary cause of climate warming and cooling:

Source: University of New Hampshire

Carbon dioxide levels over the past 600,000 years

647,000 years of carbon dioxide levels, from numerous sources:

Greenland temperatures since 1880

Average temperatures in Greenland from 1880-2010, six different stations:

Source: NASA

Does carbon dioxide cause warming?

Does carbon dioxide cause warming? This is one basic process of greenhouse gases and warming. If carbon dioxide does not cause warming, then it cannot be forcing temperatures. To answer this, we have to look at basic radiative physics. Absorption curves for major greenhouse gases have been well established for some time. For example, see the curves published Howard, 1959 and Goody and Robinson, 1951:

Using Planck's equation to overlay the amount of incoming solar radiation to outgoing thermal radiation, and you can see that the top of the outgoing thermal radiation curve aligns nicely with the carbon dioxide curve - this means that incoming light goes through the carbon dioxide but is absorbed going out.

So yes, basic radiative physics shows that carbon dioxide does cause warming.

2.1 million year record of carbon dioxide levels

A 2.1 million year record of carbon dioxide levels taken from ocean core sediment as part of the Ocean Drilling Program.

Source: Source Hönisch et a., (2009), Science.

Global Average Temperatures since 1880

Global average temperatures over a 131 year period from four different sources:

The year 2010 is essentially tied with 2005 as the warmest year on record, both warmer than 1998. This was the 34th consecutive year of above average temperatures. The last time the globe was below average was 1976.

Carbon isotope signatures in coral skeletons

Just carbon isotopes in ocean water represent the atmospheric carbon signature above, coral skeletons are reliable proxies for atmospheric changes. Taken from Swart, et al. (2010), coral skeletons from around the world show the same declining 13C/12C carbon ratio as the atmosphere above. Data from 1800 to 2000.

Short refresher on carbon isotopes: Burning of fossil fuels adds huge amounts 12C to the atmosphere which should yield declining 13C/12C ratios.

Sea Surface Temperatures in Australia

Annual sea surface temperatures in Australia from 1910 to 2010. Red line represents yearly data, while the gray columns are a 10-year running average.

Carbon Dioxide Forcing

A spectrum of the greenhouse radiation showing the effects of carbon dioxide versus other greenhouse gases (Evans et al., 2006):

And the IPCC's illustration of carbon dioxide forcing relative to other factors:

So it's clear that carbon dioxide is a strong greenhouse gas. But what about water vapor? Water vapor is also a strong greenhouse gas, but it stays relatively constant and falls out of the atmosphere quickly (as compared to carbon dioxide which stays in the atmosphere for hundreds of years). More importantly, water vapor is a positive feedback in the climate and is very sensitive to carbon dioxide warming. That is, when carbon dioxide increases and the globe warms, the amount of water vapor in the atmosphere increases as well, due to increased evaporation, and this causes the atmosphere to get even warmer. This is a well known process, and current climate models take this into account.