Natural variability can explain much of Earth's average temperature variation since the end of the last ice age, but over the past century, global average temperature has risen from near the coldest to the warmest levels in the past 11,300 years.
It’s only when we “zoom out” to the planet-wide scale that trends in surface temperature are obvious: despite a few, rare areas experiencing cooling, the vast majority of places across the globe are warming.
Concentration of carbon dioxide is about 1.4 times what it was before the Industrial Revolution. How much and how fast will Earth warm if carbon dioxide concentrations double the pre-industrial?
The most likely explanation for the lack of significant warming at the Earth’s surface in the past decade or so is that natural climate cycles caused shifts in ocean circulation patterns that moved some excess heat into the deep ocean.
Although solar flares can bombard Earth’s outermost atmosphere with tremendous amounts of energy, most of that energy is reflected back into space by the Earth’s magnetic field or radiated back to space as heat by the thermosphere.
