Remember how it used to be called "Global Warming" but then the temperature started decreasing after 1998 so they switched to "Climate Change" yuk yuk yuk?There are variations, but the basic pattern is to claim that there was some great meeting of "they" (the nebulous, rarely defined conspiracy who are orchestrating the world's greatest scientific fraud for reasons that escape any rational understanding) where perhaps some Frank Luntz-like evil marketing genius conviniced the conspirators that "Climate Change" polled better and so everyone should switch.
NASA has a good history piece on the scientific uses of both terms, and Skeptical Science has a more direct rebuttal piece to the talking point, including an amusing link to a Frank Luntz document where he explicitly advised American right wing politicians to use "climate change" because it's less frightening to average voters. As is typical of denialist conspiracy theories, the theory that "warmists" changed the terms doesn't even make sense on its own internal merits since it only decreases the urgency for action in the minds of the very people we "alarmists" are trying to alarm. We're apparently now accused of
If anyone is sincerely interested in understanding the real difference, you can read the NASA or Skeptical Science pieces, but basically "global warming" is primarily used in reference to the increasing average global temperatures (particularly surface temperatures) and "climate change" refers to a host of other climatic impacts that are not in themselves "warming" - such as changing wind and ocean current patterns, ocean acidification, changes in precipitation levels (flooding, droughts) and sometimes colder weather in places not used to it. There really isn't anything complicated here, scientists use warming in reference to warming and change in reference to changes where the primary effect is something other than hotter temperatures. The hotter global temperatures are generally the cause of these changes, but in many cases the biggest concerns about Global Warming come not from the explicitly warmer temperatures, but the secondary effects (floods will kill more people than a couple extra degrees on the thermostat).
Really though, anyone making this sort of argument can be understood to be insincere about the whole subject and only worth engaging in so much as other, actual persuadable readers might be helped to understand the mendacity of the denialist set. Underlying the factual wrongness of the argument as described above is a kind of childish pedantry where the name given to the phenomena is somehow an important point of debate in understanding what consequences it will have and what to do about it. Who cares what "they" call the changes to the climate caused by increasing atmospheric levels of greenhouse gases? Call it "worldwide greenhousism" or "international gas traps sunheat and does other stuff too" for all anyone sincere about this issue cares - just get to the imporant parts of the issue, where the fates of potentially billions of lives will be decided.
I somehow doubt if a climate change denier feels chest pains, they spend a lot of time worrying about whether to call it a "heart attack" or "cardiac arrest" before dialing 911. But that is about what this sentiment asks us to do when dealing with the Earth's growing warning signs of a major biosphere health event.