Climate Change skeptics? [ot]

Chiloe....That IS an interesting graph. It needs a "Z" axis, for volume, however.

This polar vortex excursion is a single weather event directly affecting about 2 percent of the world.
Climate change is measured by evaluating continental to global trends in weather over decades – not events happening over a few days in a little region. For this reason, a fleeting cold wave (or snowstorm) over part of a continent should never be used as evidence for or against climate change.

What's with that little uptick in volume between 2011 and 2013, that's absent from Feb to May?

MODELING RECOVERY

Our model is based on the well-known Lotka–Volterra equation of growth (the logistic equation). We model the growth of the codfish population over time, based upon initial stock size, carrying capacity, and an inherent growth rate:

B[t] = B[t – 1] + B[t – 1] r(1 – B[t – 1] /K) – B[t – 1]F

where:
B[t] is the fishable biomass (metric tons) at year t, and B[t – 1] the previous year’s biomass;
r is the inherent growth rate;
K is asymptotic carrying capacity of the ecosystem; and
F is annual fishing mortality, expressed as a fraction of the biomass.

Management options can be represented through changes in the fishing mortality F and the length of time that the moratorium (i.e., period when F = 0) continues.

The number of people supported by future cod populations depends on the amount of biomass harvested each year, B[t]F, together with the average required income. If fisher folk earn an average of P dollars per kilogram of fish, and they require an average income of I dollars from fishing, then the number of full-time jobs (J) that can be supported in year t is:

J[t] = 1000B[t]FP/I

Fish prices (P) and incomes (I) can be varied as model parameters. An interactive program incorporating equations [1] and [2], written in the Stata programming language, performed the calculations for this paper.

At the time the Northern Cod fishery was closed in 1992, the biomass was estimated to be little more than 20,000 metric tons. It continued to decline thereafter; the estimate in 1995 was down to 13,000 tons (Amaratunga 1997:55). Survey catches at this time were so poor, however, with so many 0-samples, that these estimates appear unreliable. We have set our model’s initial stock size, B0, at a possibly optimistic value of 50,000 tons. Myers et al. (1997) estimated the inherent growth rate of cod populations from many areas across the entire North Atlantic. We adopt their value for cod on the NE Newfoundland/Labrador Shelf: an annual growth rate of approximately r = 0.185. Calculations of the cod biomass in 2J3KL for 1962, when the peak distant-water fishery was just beginning, suggest that the stock then comprised around 3,000,000 tons. We use this value for K, carrying capacity. In our model runs, we arbitrarily set the desired income level at $30,000 per person.

Figure 2 depicts 100-year trajectories for biomass, under four alternative policy scenarios:

A. The moratorium continues for three more years, followed by fishing at roughly pre-collapse levels ( F = 0.30). Projected biomass rises briefly during the moratorium, but then falls after the moratorium ends. Within a few decades it approaches zero.

B. Fishing resumes immediately at an F = 0.16 mortality rate, which has been stated as a sustainable goal (unfortunately, not achieved) of pre-collapse fisheries management. Projected biomass grows very slowly, reaching just 275,000 tons (9% of carrying capacity) after 100 years.

C. Fishing resumes immediately at a “precautionary” rate (F = 0.04), equal to 1/4 of the usual F = 0.16 mortality. Growth under this scenario starts slowly but then steepens, passing 1,500,000 tons (50% of environmental capacity) in just 32 years, and 2,352,000 tons (78%) after one century.

D. Fishing is prohibited (F = 0). Biomass then approaches the maximum set by environmental carrying capacity (i.e., returns to early-1960s levels) in about 35 years. Although unlikely as policy, this scenario highlights a stark reality. Even under the strongest possible conservation rules, codfish stocks cannot rebuild to their early-60s levels within the lifetimes of many of the people now fishing.

Figure 3 shows the number of full-time jobs that might be supported under each scenario. In the long run, precautionary management would provide far more jobs—or alternatively, provide higher incomes for any number of fishers. Table 1 gives examples, showing the precautionary strategy’s 4-to-1 advantage over F = 0.16, and better than 200-to-1 advantage over a moratorium/F = 0.30 strategy, after 40 years:

actually, the term Polar Vortex has been around for many many years

It is definitely a different place. You ever climb there?