Elies Lucio

I develop a theory of how the organization of local markets shapes the effects of supply-chain regulation on illegal mining. An armed intermediary buys gold from households and sells them essential imports. What it pays for gold, it recovers through import margins. Households must cover their subsistence needs. Falling returns can make them mine more, not less. Downstream, laundering, unregulated buyers, and retention give the intermediary ways around restrictions. Restrictions can therefore change sales and receipts without changing extraction. Imperfect certification instead separates certified from unverified gold. This raises the profitability and fiscal value of legal mining. Once funded, clean innovation expands legal opportunities and the prospective tax base. Authorities who profit from illegal mining then find intervention optimal once the fiscal value of legal mining is high enough. This holds even though intervention is costly, may fail, and can be postponed. With livelihoods financed and production safe, illegal mining can end

A carbon price changes both the return to emitting and the value of an emissions allowance used as collateral. We study how these two channels affect the design of carbon taxes, tradable emissions caps and price collars, which set a price floor and ceiling.

Under jointly concave production, investment can complement or substitute for emissions. After optimising investment, firms differ in how they value emissions. We derive an exact welfare comparison between price and quantity instruments, governed by curvature and the covariance of shocks. Production complementarity alone does not determine the preferred instrument. For finite uncertainty, the globally optimal price collar can be found through a finite set of convex quadratic programmes.

We then allow firms to finance investment before receiving operating revenue. A higher carbon price can increase investment by raising collateral value, even when the direct incentive effect points the other way. Financing thresholds and a cash-equivalence result show when the share of allowances sold at auction and the timing of transfers affect real decisions. A reproducible example of joint policy design shows how the preferred revenue rule changes when public bridge finance is available. Forest conversion and Brazilian institutions identify possible applications and the data needed to assess the model.

A shared carbon market gives a firm in the South a buyer for emissions allowances it does not use. This opportunity changes the return to clean investment and, once sales are paid, the funds available to finance it. We develop a North–South investment model in which firms own emissions rights, the North advances technology and the South chooses whether to adopt cleaner or more polluting technology.

Current production and allowance prices are determined together. Firms choose investment and how much profit to retain, subject to receiving cash after investment has been paid for. We identify when cleaner production frees allowances for sale, when additional exports raise revenue despite a lower allowance price, and when Southern productivity catches up with an advancing Northern technology frontier.

A fully solved finite investment economy shows that connecting markets can increase both Southern clean productivity and the speed of relative catch-up. Under separate markets, the same cash injection instead finances polluting investment. Other parameter choices can also direct extra trading income towards polluting production. The findings are therefore conditional: the price incentive, rents from initially allocated emissions rights and later sale proceeds need to be understood separately.