Commodity exchange traded fund investors may have to hunker down over the short-term, but the commodities market could turn around further out.

Over the past year, the GreenHaven Continuous Commodity Index Fund (NYSEArca: GCC) which follows an equal-weight methodology that covers 17 commodity positions, has declined 13.9% while the PowerShares DB Commodity Index Tracking Fund (NYSEArca: DBC), which tracks a broad basket of the 14 most heavily traded commodities and uses an optimum yield methodology that tries to limit the negative effects of contango, has decreased 30.5%.

Goldman Sachs remains pessimistic over the commodities outlook for the next three months but believes things could turn around over the next 12 months, the Wall Street Journal reports.

“Despite the large declines in commodity prices, we see risks as still skewed to the downside over the near-term,” Goldman Sachs analyst said in the article.

Specifically, Goldman points to oil as a large reason for the poorer outlook as falling energy prices could continue to weigh on investment indices based on commodities in the short-term. Energy-related commodities make up a good chunk of broad commodity indices.

For instance, DBC includes heating oil 12.4%, light crude 12.4%, natural gas 5.5%, RBOB gasoline 12.4% and Brent crude 12.4%. In contrast, GCC has a 18% tilt toward energy commodities and has outperformed DBC over the past year.

Meanwhile, with oil weighing the commodities market, Goldman expects further downward pressure on copper and gold markets as well.

Even as energy prices bottom out, the oil per barrel will remain depressed for a period of time as excess supplies are stored and held on for sale in a later time when prices inch higher. Consequently, the prolonged large supply will keep oil prices from quickly bouncing back. [Oil ETFs: Investment Banks Cut Crude Outlook on Supply Glut]

Additionally, the investment bank projects copper prices will also remain low in the short-term as weaker growth, notably in China, diminishes demand. Meanwhile, Goldman holds a shaky outlook on gold as safe-haven assets lose favor. DBC includes a 8% tilt toward gold and 4.2% in copper. GCC has a 24% position in metals. [Gold ETFs Pinched by Euro Demand, Negative Analyst Chatter]

For more information on the commodities space, visit our commodity ETFs category.

Max Chen contributed to this article.