I would be amazed if any sign there were older than 1897. However, yes, you are correct that that is when the warming trend started -- somewhat earlier than the rest of the globe. You're implying that this stands in opposition to AGW. Let's review:
The foundation of AGW is based on the physical properties of CO2, specifically its absorption spectrum. This is measurable both under laboratory conditions and via satellite. Theoretically you could measure it yourself. Sunlight shines on Earth, and Earth re-radiates this same energy at a lower wavelength. This is described by the Stefan-Boltzmann Law. You can trivially calculate that, based on the incident solar irradiation and Earth's albedo, the planet should be about -18 degrees C. The effect of the atmosphere is to slow radiation leaving the Earth (the atmosphere is mostly transparent to incoming solar radiation). Outgoing radiation is absorbed and re-emitted often before it reaches space.
The lower atmosphere is already pretty much opaque to outgoing radiation; increased CO2 does not block more radiation than would otherwise be blocked. There was a point where it was theorized that no warming could occur because of this. However, it was determined that the effect of an increased partial pressure of CO2 was to extend the CO2-rich region further into space. That this increases the heat energy on the planet's surface should be obvious. The direct effect of a doubling of CO2 in the atmosphere is extremely easy to calculate, again using Stefan-Boltzmann, and it comes out to 3.7 W/m^2, which is usually considered to be equivalent to 1 degree C.
Unless you can find a new way to radiate energy to space, or unless everything we know about radiation is wrong, then the Earth must experience at least that degree of warming for a doubling of atmospheric CO2. Anything further than that is a matter for study and scientific debate, and of course the effects in different places. However, given that warming must be happening, the ability of scientists to say whether specific incidents are or are not related is more plausible.
I am glad you visited Alaska. I lived there for about 25 years, in the middle of the Chugach Mountains. There was some degree of glaciation on all of the surrounding peaks. Being in an isolated town meant that going anywhere else meant traveling across a great deal of the land. The glaciers have been melting my entire life, but the warming accelerated in the late 1990s; retreat measured in meters or tens of meters per year is very noticeable. This is very easily explained as an effect of AGW. Some other plausible explanation would be quite welcome; anything that would give me the hope of some day having the Alaska of my memory back. Unfortunately there is a great deal of science that speaks against the possibility.