Researchers at the Federal Reserve Bank of San Francisco published an estimate on Monday that complicates the timeline for U.S. interest rate cuts: the current El Niño has already lifted U.S. prices by about 0.3 percentage points between April and July 2026—and that impact, after easing through December, could return more strongly in 2027, adding up to 1 additional percentage point to inflation. For investors holding TLT or fixed-income assets tied to U.S. interest rates, the timeline just got longer than it appeared.
What Did the San Francisco Fed Conclude About El Niño?
The conclusion appears in an Economic Letter published by three researchers at the regional Fed bank: the current episode has already raised general price levels by about 0.3 percentage points in the four months between April and July 2026. The projection is that this initial effect will subside by the end of the year—but that in 2027, the same phenomenon could push prices up by as much as 1 percentage point. The World Meteorological Organization warned last month that this could be among the most intense El Niño episodes on record, bringing droughts to some regions, floods to others, and increased heat to many parts of the world.
The transmission channels are traditional: extreme weather puts pressure on crops and disrupts energy production. What sets this diagnosis apart is the source—it comes from within the Fed itself, rather than a private bank or consulting firm. That carries political weight: the Federal Reserve cannot ignore the analysis of its own researchers when calculating how much room exists to lower interest rates.
+1 percentage pointprojected impact of El Niño on U.S. inflation in 2027, according to the San Francisco Fed
Why Does Another Shock Matter Now?
The Federal Reserve has faced inflation above its 2% target for more than five and a half years—and the bill is coming due in installments. Every time the market has priced in the start of an interest rate-cut cycle, a new shock has appeared and pushed the timeline back. The San Francisco Fed study places El Niño in the same line.
The central point is that climate shocks simultaneously affect two vectors that central banks do not control directly: food and energy. When both rise at the same time, core inflation—which excludes these items—can remain well-behaved while the headline index stays elevated. This creates a communication dilemma for the Fed: cutting interest rates while headline inflation is high is risky; waiting for core inflation may be too late for the economic cycle.
The study also mentions that El Niño is expected to contribute to U.S. job creation—a positive side effect that the sources cite but do not detail. What is documented with numbers are the two inflationary impacts: 0.3 points already realized and up to 1 point projected for 2027.
What Does This Mean for Long-Term Rates—and TLT Holders?
The 10-year U.S. Treasury yield (US10Y) stood at 4.89% on Monday, easing 0.71% on the day. That daily pullback does not erase the structural takeaway reinforced by the study: inflation risks extending through 2027 provide an argument for long-term rates to remain elevated for longer than the market has priced in over recent months.
The logic is straightforward. The Fed lowers short-term rates when inflation converges sustainably toward 2%. If a 1-percentage-point shock appears on the horizon for 2027, the market prices in a slower or shorter easing cycle. Long-term bonds—which are the most sensitive to extended inflation expectations—face pressure when this equation worsens. For anyone tracking current U.S. interest rate levels and the Fed's calendar, today's study provides another data point pointing toward caution regarding the long end of the U.S. curve.
The TLT, traded in Brazil as BTLT39, rises when long-term rates fall—and that scenario moves further out of reach with El Niño on the radar for 2027. The difference between this report and a private bank's warning is that the formalization of risk by researchers within the Fed system itself enters the market's reaction function in a different way. It is not external noise; it is a signal from within the institution that sets the rate.
Why Is the Fed Still Unable to Conclude the Cycle?
The disinflation process in the U.S. has a characteristic that frustrates those expecting rapid rate cuts: every shock that seemed temporary has left a trace. PCE inflation, which printed at 3.6% in October, is another data point in this direction. This is no longer pandemic inflation; it is inflation fueled by a sequence of factors that arrived before the previous one was digested.
The San Francisco Fed study does not conclude that interest rates need to rise because of El Niño—the analysis concerns risk, not policy response. What it establishes is that the path of convergence toward the 2% target faces yet another non-trivial obstacle stretching into 2027. This diagnosis alone rules out the possibility of a rapid and generous rate-cutting cycle. For U.S. fixed income and for paper-based real estate funds (FIIs) that price risk premiums based on U.S. long-term interest rates, the effect is rate support—good for current carry, bad for the thesis of unit price appreciation that depended on falling rates.
If you hold BTLT39 (TLT), the study reinforces the argument that U.S. long-term rates will remain under structural pressure for longer—the fund rises when the market prices in more aggressive rate cuts, and that scenario is further away today. For paper-based FIIs with real estate receivables certificates (CRIs) tied to the CDI or IPCA, the high-interest-rate environment in the U.S. sustains a high risk premium in Brazil, which is favorable for carry but unfavorable for unit appreciation. Positions in U.S. fixed-rate fixed income face pressure for the same reason: the market demands more yield to lend long-term when future inflation generates doubt.
U.S. December CPI—the study projects that the initial effect of El Niño will dissipate by the end of the year. If the December 2026 CPI comes in above consensus, that dissipation has not occurred, and the 2027 impact tends to be worse. This data point serves as the most immediate barometer of risk.
Fed Statements in November and December—monitor the Fed's meeting calendar to see whether FOMC members begin citing climate risk explicitly. Mentioning El Niño as a risk factor in minutes or post-meeting statements would signal that the topic has entered the formal reaction function.
US10Y Above 5.0%—the current level of 4.89% is close to that threshold. Any data reinforcing the inflationary narrative could push yields toward that level, which would again pressure Brazilian FII valuations and growth equities that correlate with the U.S. yield curve.
