no warming?

for the first time on record, the arctic ocean has gone 2 years without icing over.

for the first time ever, folk in fairbanks needed air conditioning last summer.

average world temperature is neither constant nor always rising. various factors cause natural fluctuation. snow and ice, for example, reflect into space 90% of the sunlight that strikes them, so they tend to cool the planet. in contrast, melted sea ice becomes dark water, which absorbs 90% of light energy, so it gets warmer, accelerating the effect by melting more ice.

the greenhouse effect is another natural process. various atmospheric gases, including carbon dioxide, methane, CFCs, nitrous oxide, and ozone, are transparent to visible light but reflect infrared. sunlight gets absorbed by most of the planet's surface during the day, then released as heat, much of it when temperatures drop at night. the radiant component of heat is infrared, which may escape into space or bounce back when it hits molecules of greenhouse gas.

the amount of methane in the atmosphere was constant till 300-400 years ago, when it began to rise at about the same time as the till-then nearly-constant human population began to grow. that's most likely due largely to a rising need for fuel and building materials: when trees get cut down, the termite population in the ground multiplies many times, and termites produce an enormous amount of methane. cattle and sheep are also methane sources. more humans led to bigger herds as demand grew for meat, milk, leather, wool, &c.

the industrial revolution accelerated carbon dioxide emission, already growing from rising wood-burning, as coal and then petroleum got used more by factories and vehicles.

some of the greenhouse effect can get offset by airborne particulates, which screen out sunlight. in the 1950s and '60s, for example, the world became relatively cool till particulate pollution got cut in response to serious health concerns.

the current average world temperature is only 5° higher than it was in the depths of the last ice age, but it's grown 1° in the last century. 2005 was either the hottest or 2nd-hottest in at least 2k years.

nearly all glaciers are now receding, including polar icecaps.

falling arctic ocean salinity may stop the gulf stream.

storms appear to be growing in intensity.

malaria-carrying mosquitos are flying to higher altitudes and higher latitudes.

i could go on.