How much can El Niño be blamed for the jump in CO2?

Something unusual happened in April this year. Between March and April there was a record month to month jump in atmospheric CO2 recorded at Mauna Loa. It went up by 2.71 ppmv. That's 0.6 ppmv higher than the previous highest month to month jump (2.11 ppmv) back in April 2004. However it's not wise to focus on month to month variations. For example, March could have been lower than expected, which would make the jump seem larger than it should be. (It wasn't.) This article explores some of what causes atmospheric CO2 to go up and down. It's not the answer to everything, however I learnt a lot doing the research and I have some unanswered questions too (like a quantitative answer to the title of this article). (Let me know if you see any mistakes I may have made.)

The chart below shows the month by month increase in atmospheric CO2 since the late 1950s. Hover over the chart for the values. The most recent is April at 407.57 ppmv.

Figure 1 | Monthly CO2 at Mauna Loa. Data source: SCRIPPS CO2 Program

WUWT trips over p's and H's in the ocean

Here's another teaser on oceans and acidification. I've got another article in train but have been busy, so it won't be up for a while longer. Meanwhile, WUWT has another "claim" article (archived here) about a not so new paper on ocean acidification,  total CO₂ concentration and the degree of CaCO₃ saturation (from June this year).

The paper itself is by a team led by Professor Taro Takahashi and has been published in Marine Chemistry. Anthony copied and pasted the press release but didn't have time to link to the source :) Never mind. It wasn't hard to find. The press release is on the website of the Earth Institute of Columbia University. I don't know why it has just been released. The paper itself has been out for a while. It looks to be a continuation of the work discussed in this paper from 2010, which itself built on work done prior. In fact, as stated in the press release, Taro Takahashi has been doing this research for four decades.

Taro Takahashi has spent more than four decades measuring the changing chemistry of the world’s oceans. Here, aboard the R/V Melville, he celebrates after sampling waters near the bottom of the Japan Trench in 1973. (Lamont-Doherty archives)

In a nutshell, the scientists have published maps of the world's oceans, showing:

... a monthly look at how ocean acidity rises and falls by season and geographic location, along with saturation levels of calcium carbonate minerals used by shell-building organisms. The maps use 2005 as a reference year and draw on four decades of measurements by Lamont-Doherty scientists and others.