ClimateHQ: Hot or Not?

Ocean heat content at different depths since the 1950s

Ocean heat content at varying depths since the 1950s. Note the pronounced warming since the late 1990s:

From Balmaseda, et al., 2013, Geophysical Research Letters.

Ocean heat content through 2012

Measured in the upper 2000m of the ocean:

11,300 global average temperatures

An 11,300 year global average temperature reconstruction using proxies from 73 worldwide sites, from Marcott et al., Science, 2013:

Sun's Energy Output since 1970s vs Global Surface Temperature

Is the sun's output driving increased temperatures? Here is a graph from the National Climatic Data Center comparing our sun's energy output since the 1970s with global average surface temperatures:

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.