Jim360 - "... The last 18 years have also included several of the warmest on record, so that the world hasn't warmed up all that much during that time is quoting only half of the data, and potentially rather misleading..."
You say that, but is it really true? We've had ground-based stations (Stevenson screens or boxes) [SB's] for over a hundred years:
https://en.wikipedia.org/wiki/Stevenson_screen
SB's are thermometers placed in weather-proof boxes in various locations around the world. Some are well maintained. Some are not. What they essentially do is measure temperature at ground level (or just above it). However, they are subject to a myriad of factors that call their accuracy into question. First there's the question of instrumentation failure/bias (ie. is the equipment in the box measuring the temperature correctly?). Then there's user error (ie. an incorrect visual reading of the temps.). Then there's the fact that almost all of the SB's have little or no record of whether or not they've been moved - and a great deal have, often more than once, meaning that their recording history is deeply flawed. Then there's the matter of urbanisation and the attendant urban heat island effect (UHIE). The UHIE as you will know means that lots of concrete at asphalt in towns and cities retains heat from the sun during the day and cools more slowly than any surrounding rural areas. Urban environments can be many degrees higher both during the day and at night than their more rural surroundings. Then there the process of "homogenisation" that artificially alters the temperature records by making the past appear cooler and the present appear warmer thus exaggerating the current "warming" trend. This is a mathematical technique originally used in geological investigations (gold mining in particular) that has been fundamentally miss-applied to the temperate record. This flagrant methodological fudge is an outrageous statistical fraud and worthy of a discussion on its own.
So is it true that the past few years have seen record temperatures? If you believe the ground-based station record that has been manipulated then, yes it has. However, if you look at the RSS satellite data, it tells a very different story. The satellite date isn't subject to the inherent problems that the SB's have. The satellite data is the most accurate record of temperature we have. Unfortunately, we've only had it since the late 1970s but what it says is that there has been no statistically significant global warming for nearly 20 years. The trend line for temperature increase is zero. For almost a generation, there has been no warming of the Earth.
Having said all this, let's take a look at the claim that the recent years have been the hottest ever. It was reported in the press that 2014 was the warmest year ever recorded. This claim, made by NASA, said that 2014 was the hottest year ever by... 0.02C: a figure so small that it lies outside of the error bars of measurement (ie. a figure that cannot be verified by any physical thermometer but which has been derived through maths). However, after NASA's press release - that was picked up by almost every national newspaper on the planet and reported as fact - it emerged that the truth was somewhat different. According to Gavin Schmidt (of NASA's GISS [Goddard Institute for Space Studies]) the likelihood that 2014 was the warmest year since 1880 is 38%.
Now, I'm no mathematician, but if someone is only 38% sure they may be right, then it stands to reason that they're 62% sure that they may be wrong.
What rational person would confidently conclude that 2014 was the hottest year on record when the accuracy of the measurement is beyond what we are physically capable of measuring and the confidence of the result is less than can be attributed to random chance?
Further reading about the NASA GISS result:
http://goo.gl/L1lfHu