Liar: Last week an Obama tweet blamed Hurricane Sandy and wildfires on climate change...

The dangers of extreme weather can be heartbreaking. It's time to #ActOnClimate. pic.twitter.com/hfGTXht97h
— Barack Obama (@BarackObama) October 29, 2014

NOAA disagrees: (Accent is mine)

Concerning the issue of whether storms (Sandy and the nor’easter) are signals of the impact of climate change on extreme weather:

• No significant increase in Atlantic hurricanes since the late 1880s has been observed.

• The number of hurricanes that make U.S. landfall has not significantly increased or decreased.

• In the future, it is likely that global frequencies of tropical cyclones will either decrease or remain essentially the same as a result of projected greenhouse gas induced climate change, though rainfall rates related to such storms are likely to increase.

• There is low scientific confidence that overall storminess has changed, however, it is likely that there has been a human-induced increase in coastal extreme sea level events due to overall sea level rise.

Researchers a the highly respected CSU Department of Atmospheric Science disagree:

Researchers at Colorado State University say the devastation caused by Hurricane Sandy in October was not caused by human-induced climate change.
In a recently released paper discussing the unusual “super-storm” that devastated the New Jersey shore and flooded the New York City subway and a traffic tunnel, CSU researchers William Gray and Phil Klotzbach say the influence of human activity on the formation and intensity of Atlantic hurricanes “is likely to be negligible.”
“As extensive and tragic as Sandy’s spawned destruction has been, it is not beyond the range of what is known about the variability of rare but extreme cyclone events,” Gray and Klotzbach wrote.
The researchers acknowledge that human activity has led to an increase in carbon dioxide being released into the Earth’s atmosphere and an increase in average temperature. But Gray and Klotzbach do not think that has caused more frequent and powerful hurricanes to form.

As for the claim climate change is causing more wildfires, that is false too.  Data (1960 on right) from nifc.gov.