Annual layers in ice deposits in Greenland, and especially in Antarctica, are observed which give records of the climate in the year each layer was deposited. The upper layers of these deposits correlate with other methods of measuring recent climate, but from there the layers continue to give a continuous record of the yearly climate for the past 160,000 years (see C. Lorius et al, Nature, v.316, pp.591-596 (15 Aug 1985); J. Jouzel et al, Nature, v.329, pp.403-408 (1 Oct 1987); J.M. Barnola et al, Nature, v.329, pp.408-414 (1 Oct 1987)). Among the many discernable patterns, the 26,000-year climate cycle due to the precession of the Earth's rotation axis (that is, the Earth "wobbles" like a top, and the rate of its 26,000-year cycle can be calculated from physics alone) is clearly visible throughout the 160,000-year record. This refutes the young-Earth claim that perhaps the lower layers of the ice cores were built up quickly due to large precipitation rates from Noah's Flood. A young-Earth attempt to explain away this evidence (ICR Impact #226, http://www.icr.org/pubs/imp/imp-226.htm) talks mostly about issues that are irrelevent to the Antarctic data, and its only attempt to challenge the above-cited data is to quote a statement from 1972 that deeper annual layers are more difficult to measure, a difficulty that was solved by superior technology by 1985. It is important to note that, if this is a case of "apparent age", God would have not only created these layers for no apparent reason, but would have "written" into the ice a climate record that cannot be trusted. Such a theory results in serious difficulties with the truthfulness of God. A similar situation applies to sedimentary varves (annual layers from lake sediments). Varves in Utah's Green River Formation give several million years of unbroken history. Evaporite deposits, in which one layer is formed each time a shallow body of water is evaporated dry, also contain records at least hundreds of thousands of years long. Finally, paleomagnetism, the science that studies the reversals of Earth's magnetic field as recorded in rocks, has worked out a consistent history of Earth's magnetic field stretching back hundreds of millions of years, correlated across the entire globe.