2010 joint warmest on record; most of 2000s in top 10

Top Ten Global Weather/Climate Events of 2010
Rank	Event	When Occurred	Description
Source: Top Ten Global Weather/Climate Events of 2010 National Climatic Data Center, NOAA, December 2010 These lists were compiled and voted on during the first week of December. Significant events, such as the extreme winter weather in Europe and the flooding in Australia occurred after this date. These events have been included in an additional section titled, “Honorable Mention”, but may have warranted top ten placement.
1	Russo- European- Asian Heat Waves	Summer	A severe summer spawned drought, wildfires and crop failures across western Russia, where more than 15,000 people died. All-time high temperatures occurred in many cities and nations in the region. China faced locust swarms during July.
2	2010 as [near] warmest on record	Calendar Year	According to NOAA, the globally-averaged temperature for 2010 will finish among the two warmest, and likely the warmest, on record. Three months in 2010 were the warmest on record for that month.
3	Pakistani Flooding	Late July into August	Rainfall related to the Asian Monsoon was displaced unusually westward, and more than a foot of rain fell across a large area of the Upper Indus Valley. Subsequent flooding down the Indus River killed 1,600 people and displaced millions.
4	El Niño to La Niña Transition	Mid-to-Late Boreal Spring	ENSO, the most prominent and far-reaching patterns of climate variability, saw a huge swing in mid-2010. Only 1973, 1983 and 1998 have seen larger within-year swings.
5	Negative Arctic Oscillation	December–February	The AO Index, which is strongly correlated with wintertime cold air outbreaks, reached -4.27 for February, the largest negative anomaly since records began in 1950. Major cold air outbreaks occurred throughout the Northern Hemisphere.
6	Brazilian Drought	Ongoing	A severe drought parching northern Brazil shrunk the Rio Negro, one of the Amazon River's most important tributaries, to its lowest level since records began in 1902 at its confluence with the Amazon. The Amazon's depth there fell more than 12 feet below its average.
7-tie	Historically Inactive NE Pacific Hurricane Season	May 15th–November 30th	The Northeast Pacific Hurricane Season was one of the least active on record, produced the fewest named storms and hurricanes of the modern era, and had the earliest cessation of tropical activity (Sep 23) on record.
7-tie	Historic N. Hemispheric Snow Retreat	January through June	Despite December 2009 having the second-largest snow cover extent of the satellite record (mid-1960s), the melt season was ferocious, contributing to spring floods in the Northern U.S. and Canada. Following the early and pronounced snow melt, the North American, Eurasian and Hemispheric snow cover was the smallest on record for May and June 2010.
9	Minimum Sea Ice Extent	Mid-September	The 2010 sea ice minimum of 4.9 million sq km was the third smallest on record. The last four years (2007-2010) are the four smallest on record. The Northwest Passage and the Northern Sea Route were simultaneously ice-free in September, a first in modern history.
10	China Drought	First half of 2010	A persistent drought centered in the Yunan Province was touted as perhaps the worst in this region in more than 100 years. Major crop losses and lack of drinking water created severe problems for local residents.

The additional concern, as meteorology professor Scott Mandia explains, it can take decades for the climate temperatures to increase in response to increased greenhouse gas emissions. So up until now, perhaps it has been easier for skeptics to deny climate change is occurring or that humans are responsible.
But as this infographic shows, most of the warming is going into the oceans:

Source: John Cook, Infographic on where global warming is going, SkepticalScience.com, January 20, 2011 (further notes on the source data used)

As John Cook, creator of the graphic above says (see above link), “Just as it takes time for a cup of coffee to release heat into the air, so to it takes time for the ocean to release its heat into the atmosphere.”.
The implications of this is further explained with Inter Press Service’s freezer analogy: The world’s northern freezer is on rapid defrost as large volumes of warm water are pouring into the Arctic Ocean, speeding the melt of sea ice.
Indeed, as this chart also shows, the warming in the oceans has been occurring for quite some time:

Source: John Cook, The Earth continues to build up heat, Skeptical Science, October 12, 2011

One of John Bruno’s colleagues, Ove Hoegh-Guldberg, talks about the impact climate change will have on ocean ecosystems. A summary of the video here says that

Ove Hoegh-Guldberg NCSE talk on climate change impacts on ocean ecosystems, Climate Shifts, January 21, 2011.

“Rapidly rising greenhouse gas concentrations are driving ocean systems toward conditions not seen for millions of years, with an associated risk of fundamental and irreversible ecological transformation. Changes in biological function in the ocean caused by anthropogenic climate change go far beyond death, extinctions and habitat loss: fundamental processes are being altered, community assemblages are being reorganized and ecological surprises are likely.”
D. Salmons also has a post at Skeptical Science that explains the impact of warming Arctic’s relation to the very cold recent winters further, using the following NASA map:

Source: GISS Surface Temperature Analysis, NASA Goddard Institute for Space Studies, accessed January 30, 2011

As Salmons explains,
the Arctic has been heating up, and studies show that is happening at two to three times the global average. This rising temperature in the Arctic has served to reduce the region’s floating ice layer by more than 20%. And as you would expect, when the reflective ice and snow layer is stripped away, it leaves a dark blue sea.
Now, what does the effect of the dark blue sea being exposed have on the Arctic area? Well, the ice and snow layer reflects the majority of the sun’s rays harmlessly back into space. But the dark blue of the exposed sea absorbs the rays, aiding the heating process.

— D. Salmons, Global Warming and Cold Winters, Skeptical Science, January 15, 2011

2010 joint warmest on record; most of 2000s in top 10

NASA’s GISS Surface Temperature Analysis graph shown earlier (from 1800 to 2010) shows that temperature anomalies since 1980 have all been positive; i.e. it has been constantly hotter than normal.
As the same data shows, the hottest years have all been since 1998:

Global Top 10 Warmest Years (Jan-Dec)	Anomaly °C	Anomaly °F
Source: Annual State of the Climate Global Analysis, National Climatic Data Center, NOAA, December 2010
2010	0.62	1.12
2005	0.62	1.12
1998	0.60	1.08
2003	0.58	1.04
2002	0.58	1.04
2009	0.56	1.01
2006	0.56	1.01
2007	0.55	0.99
2004	0.54	0.97
2001	0.52	0.94

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