Archive for December, 2015


As most of us learned in elementary school, plants require carbon dioxide to create carbohydrates in the photosynthesis process. It is also true that warmth can improve photosynthetic productivity. If these things are true, it should follow logically that increasing atmospheric carbon dioxide concentrations and temperatures should improve productivity in plants. As with most myths concerning climate change and its effects, perpetuated by climate change skeptics, there is some truth to this. However, as with many claims made by skeptics, it omits the bigger picture.

In lab tests, it has been shown that increasing carbon dioxide concentrations in the air has a linear relationship with internal leaf concentrations. However, internal carbon concentrations eventually level off once the plant is saturated, and is limited by the availability of photosynthetic enzymes (also known as carboxylation enzymes).This lowers the CO2 to O2 ratio, and this encourages photorespiration, which in turn emits CO2 as a waste product [1].


Thus, increases in atmospheric CO2 can only be expected to improve plant growth to a point, whereupon increased photorespiration will become a positive feedback in the global carbon cycle.

Similarly, there is an optimum temperature at which plants can photosynthesize. There is evidence that when plants are stressed by temperature (either too high or too low), photosynthetic productivity is impaired, and that there is a relationship between the duration of the stress and the degree of severity, and the impact to photosynthetic capacity. In both frosts and heat stress, there is a lag time between when the stress ends and when photosynthetic productivity is repaired. Furthermore, evidence suggests that while plants can usually recover from a frost, heat stress can lead to more permanent damage. [2]

Temperature, unlike carbon concentrations, follows a parabola, where photosynthesis follows a linear trend until it reaches an optimum range, (for most plants this is between 59 and 77 degrees fahrenheit), whereupon photosynthetic productivity declines [3].


Furthermore, increasing temperature leads to lower internal CO2 to O2 ratios, again encouraging photorespiration, and thus increasing CO2 output. Even when CO2 levels are maintained, photosynthesis decreases at high temperature due to changes in chloroplast and enzyme activity.

Finally, limiting exposure to water, as climate change is sure to do, due to the increase in drought frequency, causes stomata closure, so the amount of CO2 that can diffuse to the mesophyll cells decreases, limiting photosynthetic production. If leaves lose enough water stomatal closure completely restricts the flow of CO2. Furthermore, there is a threshold where partial closure limits diffusion and uptake declines sharply. This decline in CO2 also favors photorespiration. [4]

In the case of chronic drought, (as we have been witnessing since the mid-2000s in the Western United States),  photosynthetic enzymes are broken down, reducing the capacity for photosynthetic activity. Chlorophyll is also reduced.


As can be seen, there is a limited amount of truth in the skeptic’s argument about increasing photosynthetic activity. All of the processes by which this could occur have limits, and even eventually damage plants when taken to extremes. Ecosystems tend to function within sensitive optimum limits, in regards to all the operable variables. Thus, it is important that climate conditions as well as carbon dioxide concentrations be kept within the optimum range, lest we introduce positive feedbacks.


Works Cited:

[1] Forest Ecosystems: Concepts and Management – Richard H. Waring, William H. Schlesinger pg. 13

[2] pg. 14-15

[3] pg. 15

[4] pg. 16


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Many worried, going into COP 21, that we’d have a repeat of Copenhagen, where the world’s powers (especially the United States) drag their feet on making a deal, while some remain in complete denial of the problem. As the scientific consensus has grown stronger in the past decade, the American people still believe that there is a debate about the cause of climate change. While there is room for dissent in science, and the scientific community has occasionally been wrong, it is fair to say that there is next to no debate about what is causing climate change. The only remaining debate in the scientific community is over how bad warming is likely to be, (though most expect well over the targeted 2 degrees). As a result of the state of politics, many feared deadlock, and a refusal to acknowledge what the scientific community has had evidence of for more than 30 years, and has been sure of for probably the last 15.

With the state of politics the way they are, most admit that any deal, at all, is a victory. The United States has touted itself as a major leader on climate at COP 21, but it was, in fact, the United States that dragged its feet over many aspects of the deal being legally binding. For instance, the US pushed for monetary aid to nations afflicted by climate change to be voluntary, and for targeted emissions reductions to also be voluntary. This is likely a reflection of domestic politics, since congress passed a bill recently blocking any budgetary appropriations for climate change, and some republics have decried that attention be given to climate at all, in the wake of the Paris shootings. With this being the state of affairs, one cannot help but wonder if all the praise for a climate deal was the world’s leaders patting themselves on the back prematurely, simply for having come to any agreement at all…

Sure, the wording of the deal sounds nice.

Emphasizing with serious concern the urgent need to address the significant gap between the aggregate effect of Parties’ mitigation pledges in terms of global annual emissions of greenhouse gases by 2020 and aggregate emission pathways consistent with holding the increase in the global average temperature to well below 2 °C above pre- industrial levels and pursuing efforts to limit the temperature increase to 1.5 °C above pre- industrial levels. [1]

But if this is merely a suggestion, how can we expect any party to consistently hold themselves to it. Furthermore, the United Nations has long been a governing body that lacks the authority necessary to actually make progress (on anything). If none of the agreement bears the weight of an international treaty, then how can we expect to raise the necessary $23 trillion necessary to wean the developing world off of carbon heavy energy sources?

If the deal had been legally binding, on the other hand, it would have never been approved by the US congress, leaving the world’s biggest per-capita carbon emitter out of the deal completely. But that doesn’t change the fact that this is largely just a legacy piece for the Obama administration, and means even less than Kyoto, which was also never passed into US law, and thus easily overturned by the Bush administration.

All of the “victories” of the climate deal will do absolutely nothing to change the way we live, and to preserve a planet that is clearly suffering at our hands. None of it address that we’ve already lost 1/3 of earth’s arable land, and that forest pests, fires and droughts are all already more common and more severe. The only “meaningful” victory was to prevent China and India from taking money from the developing nations fund, even as their economies continue to grow well beyond the bounds that would be defined as “developing.”

It seems, to me at least, that policy on the world scale is probably impossible in a democratic setting, and it has already gotten about 20 years behind the science thanks in part to a massive, multi-million dollar disinformation campaign, on the part of oil, coal and natural gas producers. We’ve already likely damned ourselves to the 2 degree rise many scientists consider the breaking point, beyond which the system will cease to function in the predictable manner we’ve come to rely on for our civilization, as a result of positive feedbacks we’ve introduced. (See bifurcation in complex systems). As far as I can tell, this “agreement” does little more than kick the can to the next conference, in the hope that the free market will decide to voluntarily take actions — which is ironic because climate change is by definition a market failure.


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As the climate conference in Paris pushes into its second week, it appears that a draft agreement may have been reached. According to those present at the conference there still remains the vital sticking point of financial responsibility. Particularly, how much responsibility do industrialized nations have toward developing nations, to help prevent them from emitting fossil fuels in the process of development.

Currently, the world gives $452 billion annually to the fossil fuel industry, and developed nations as well as oil rich nations have often dragged their feet in climate negotiations, due to dependence on cheap energy. Suadi Arabia, a nation that gets the vast majority of its wealth from oil sales, has unsurprisingly been blocking any reference to 1.5 degrees Celsius as the temperature above which catastrophic events could occur. Previously, 2 degrees had been touted, but recently many small island nations have noted that 2 degrees would represent an existential threat for them. Also unsurprisingly, Saudi Arabia has claimed to have no funds available to help developing countries invest in renewable energy and other emission reducing initiatives. Saudi Arabia was the last of the G20 nations to submit their national climate plan, the plan included no details to lower emissions, nor did it include current level of emissions. Again, none of this is surprising, considering Saudi Arabia earns 90% of its GDP from oil revenues, so it has little incentive to negotiate for strong carbon reductions.[1] [2]

Somewhat surprisingly, Russia, another nation that gains substantial portions of its wealth from fossil fuels, came out strong at the Paris Conference. Russian President Vladimir Putin promised to reduce emissions by 70% of 1990 levels by 2030. He called climate change “one of the greatest threats humanity is facing,” and reminded the conference that Russia has already reduced emissions.[3] However, many suspect that Putin’s remarks were only platitudes, and the substance necessary to make a significant deal. After all, Putin has played the role of climate change skeptic in the past, and Russia stands to gain access to natural gas in the arctic, should sea ice melt.

Iceland’s Prime Minister Sigmundur David Gunnlaugsson noted that the effects of climate change are already noticeable in Iceland. In Iceland, glaciers are already noticeably retreating, he suggests his country will be a sort of classroom for studying the changes. He notes that “without efforts to decrease emissions, glaciers in Iceland could disappear for the most part in 100 years.” Iceland, he said, gets “almost all of our energy for electricity and for heating houses from renewable energy sources.” [4]

Denmark, on the other hand, would like to halve the financial support it gives to vulnerable developing countries, to help them cope with the impacts of climate change. Denmark was formerly a leader in addressing climate change. The nation, which negotiates on behalf of Greenland, (a landmass covered in ice, the loss of which is expected to contribute significantly to sea level rise), has revised its goal of reducing emissions 40% below 1990 levels by 2020 to just 37%. As a result of their poor showing at COP21 the Climate Action Network has awarded Denmark the “Fossil of the Day,” award, dedicated to nations that have the poorest showing at the climate conference.

As has often been the case, the United States suffers from a lack of credibility at the conference, because, while the executive branch supports a climate deal, congress has already moved to block any progress. Many developing countries are concerned that the U.S. will not be able to keep its funding commitments, because the Republican congress is threatening to block any appropriations for international climate assistance. As a result the Obama administration is pushing back against a legally binding agreement, since it would certainly fail in congress. Furthermore, the United States has fallen out of step with many allies, including Canada and the European Union, who are now calling for a limit of 1.5 degrees Celsius warming. The United States maintains the negotiation position of 2 degrees.[5]

On Saturday, nearly 200 nations agreed to a draft agreement, to hold increase in global average temperature to below 1.5 degrees Celsius, or well below 2 degrees above preindustrial levels, by ensuring deep reductions in global greenhouse gas emissions, to increase the ability of nations to adapt to the adverse impacts of climate change, and to pursue a transformation towards sustainable development. This draft agreement still leaves a lot to be negotiated, and with this year on pace to be the warmest on record, the stakes have never been higher. The conference is set to expire on Friday, so the week ahead will be vital in defining the path forward, for a world already in crisis. [6]

[1] http://sputniknews.com/environment/20151206/1031330666/saudi-arabia-undermining-climate-deal.html

[2] http://www.climateactionprogramme.org/news/saudi_arabia_submits_climate_plan_for_cop21_global_deal

[3] http://www.cnn.com/2015/11/30/europe/france-paris-cop21-climate-change-conference/

[4] http://icelandreview.com/news/2015/12/01/pm-cop21-climate-change-visible-iceland

[5] http://www.theglobeandmail.com/news/world/climate-talks-hinge-on-financing-for-developing-nations/article27626639/

[6] http://www.npr.org/sections/thetwo-way/2015/12/05/458575455/nearly-200-nations-agree-on-climate-change-draft-plan-at-paris-summit

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