Can Sustainable Investing Reduce Pollution? A Structural Analysis of ESG Capital Allocation

As part of the Austria Pollution Awareness Campaign, I have focused primarily on environmental measurement and public awareness. However, pollution is not shaped by policy and behavior alone. It is also shaped by capital allocation.

If investment capital continues to flow toward high-emission firms, environmental transition becomes structurally constrained. This raises an important question: does “sustainable investing” actually reduce pollution exposure, or does it simply track the same market with different branding?

To explore this, I conducted an independent quantitative comparison of two major U.S. equity ETFs:

• VOO: Vanguard S&P 500 ETF (broad-market benchmark)

• SUSL: iShares ESG MSCI USA Leaders ETF (ESG-screened index)

While these funds are U.S.-based, they hold multinational firms whose operations, supply chains, and environmental impacts are global, including in Europe.

Carbon Exposure and Capital Allocation

To measure environmental exposure, I weighted each company’s Scope 1 (direct) and market-based Scope 2 (electricity-related) emissions by its share of the portfolio. This reflects pollution exposure relative to invested capital.

Among the top 20 holdings (about two-thirds of each portfolio):

• VOO weighted emissions: 1,764,944 tCO2e

• SUSL weighted emissions: 368,020 tCO2e

VOO’s capital-weighted carbon exposure is nearly five times larger.

The difference is driven by concentration. In VOO, Exxon Mobil and Amazon account for approximately 88% of total weighted emissions. When high-emission firms remain heavily weighted, pollution exposure becomes structurally embedded in the portfolio.

SUSL reallocates capital away from fossil-fuel-intensive firms. Its largest contributor is Alphabet, primarily through electricity consumption rather than fossil-fuel extraction. The overall effect is not uniform decarbonization, but a meaningful shift in exposure concentration.

This demonstrates that capital markets can influence pollution exposure by changing which firms dominate investment flows.

Financial Behavior

Environmental divergence does not imply financial detachment from the broader market.

Weekly returns in 2024 were nearly identical:

• VOO: 0.49%

• SUSL: 0.47%

Return correlation was extremely high (0.987), meaning both funds moved almost identically with overall market conditions. However, SUSL exhibited slightly higher market sensitivity (beta ≈ 1.13) and higher volatility. In rising markets, this amplifies gains; in falling markets, it amplifies losses. ESG screening preserved broad market integration while modestly altering risk sensitivity. This suggests that investors can reduce pollution exposure without fundamentally sacrificing market alignment.

Investor Attention

I also examined whether shifts in public search interest influenced ETF performance. Correlations between weekly search changes and returns were weak (all below 0.20). At the ETF level, macroeconomic forces dominate short-term behavior. This indicates that structural capital allocation, rather than temporary attention spikes, drives long-term environmental exposure differences.

Why This Matters for Pollution Awareness

Pollution is not only a regulatory issue. It is also a capital allocation issue. If investment capital concentrates in high-emission firms, environmental harm remains embedded in financial systems. ESG screening does not eliminate emissions entirely, but it can significantly reduce capital-weighted pollution exposure.

For a campaign focused on pollution awareness in Austria and Europe, this reinforces an important point: environmental change operates through systems: policy systems, behavioral systems, and financial systems. Reducing pollution requires not only awareness and regulation, but also examining how capital flows shape environmental outcomes.