Nicolas Piluso

The paper analyzes the effects of introducing a corporate carbon tax on GDP and the effectiveness of this macroeconomic policy. The study is based on constructing a simple Keynesian model with flexible prices. It shows that the carbon tax can have a double beneficial effect on the economy in addition to its favorable effect on the environment: i.e., an increase in GDP and employment. The initial values (y = 100; C = 60; I = 18; G = 16; g(A) = 6) was used to simulate a positive shock of the carbon tax T, increasing from 1.75 to 1.9. The paper considers three different cases depending on the low (Case 1), medium (Case 2), or high (Case 3) sensitivity of the marginal propensity to consume in response to an increase in the prices of goods. In addition, case 4 is considered: stimulus policy associated with climate policy; and case 5 is: policy to increase nominal wages. The results show that the carbon tax can lead to an increase in prices. Although the tax does not excessively negatively affect consumption, it has a positive effect on GDP via the increase in green investments and the induced increase in public spending. Households are, therefore, not necessarily penalized because they benefit from the multiplier effects of the increase in public spending due to the introduction of the ecological tax. Furthermore, stimulus policy is even more effective when combined with an emissions tax.

The carbon market reform is controversial because the modalities of carbon pricing foreseen risk reducing the performance of companies and negatively affecting the economy. The objective of this paper is to show that the carbon tax can be floating and adapt to the economic situation while maintaining its ecological efficiency. Herein, Tobin’s Q model, which has become a standard in the literature for explaining the investment decision, is applied to the green investment decision. A carbon tax is introduced into the firm’s maximization program to see how carbon pricing changes the outcome of the traditional model. The model shows that green investment depends on the sum of the stock price and the carbon price, which suggests the possibility of modulating this amount according to the upward or downward trend of the stock price to avoid permanently penalizing the competitiveness of firms. The study also demonstrates how the financial market is likely to value green investments and that such investments will likely generate shareholder value through several channels. Indeed, green investments impact the firm’s turnover and the minimum income required by the shareholder. Such a modulation of the carbon tax according to the economic cycle would make reconciling ecological and economic efficiency possible.

Given the global climate emergency and the complex financing problems facing developing countries, some economists are advocating the introduction of payments for environmental services. The question is whether payments for environmental services will enable developing countries to make the ecological transition compatible with the economic growth they need to develop. This study presents a theoretical analysis of the economic and ecological efficiency of such a mechanism, and aims to determine whether it has any recessionary or disincentive effects. In other words, it determines whether, from a theoretical point of view, the environmental services provided by developing countries are compatible with continued growth. The study introduces a “payments for environmental services” procedure into a general equilibrium model (with involuntary unemployment) composed of multinational firms in developed and developing economies. This theoretical model yields the following results. Firstly, higher ecological taxes can directly increase environmental services without any recessionary effect. The system of payments for environmental services means that green investment is not necessarily incompatible with growth and development in developing countries. On the other hand, services in return for environmental payments can lead to a rebound effect from polluting activities, which is why such programs need to be accompanied by more radical environmental policies. In conclusion, while payments for environmental services can promote both ecological transition and growth in developing countries, it is necessary to control the rebound effect arising from the development of economic activity.